速查手册

硬度换算表（HRC / HV / HB / HRA，ASTM E140）

近似换算，依据 ASTM E140；不锈钢与非铁金属可能有差异。

HRC	HV（维氏）	HB（布氏 3000kg）	HRA	近似抗拉强度 MPa	近似抗拉强度 ksi
70	1076	—	85.6	—	—
69	1004	—	85.0	—	—
68	940	—	84.4	—	—
67	900	—	83.9	—	—
66	865	—	83.4	—	—
65	832	—	82.8	—	—
64	800	—	82.2	—	—
63	772	—	81.7	—	—
62	746	—	81.1	—	—
61	720	—	80.4	—	—
60	697	—	79.8	—	—
59	674	—	79.2	2290	332
58	653	—	78.5	2220	322
57	633	—	77.8	2150	312
56	613	—	77.1	2080	302
55	595	—	76.5	2010	292
54	577	—	75.9	1950	283
53	560	528	75.3	1890	274
52	545	512	74.7	1840	267
51	529	496	74.0	1790	260
50	513	481	73.4	1740	252
49	498	466	72.7	1680	244
48	484	451	72.0	1630	236
47	471	437	71.4	1580	229
46	458	423	70.7	1530	222
45	446	410	70.0	1480	215
44	434	397	69.4	1440	209
43	423	385	68.7	1400	203
42	412	373	68.1	1360	197
41	402	362	67.4	1320	192
40	392	352	66.7	1280	186
39	382	341	66.0	1240	180
38	372	331	65.3	1200	174
37	363	322	64.7	1160	169
36	354	313	64.0	1130	164
35	345	304	63.3	1100	159
34	336	295	62.5	1060	154
33	327	287	61.8	1030	149
32	318	279	61.1	1000	145
31	310	270	60.4	970	141
30	302	262	59.7	950	138
29	294	254	59.0	920	134
28	286	247	58.2	900	131
27	279	240	57.5	880	128
26	272	233	56.8	860	125
25	266	226	56.1	840	121
24	258	219	55.3	810	117
23	252	213	54.6	790	115
22	246	207	53.8	770	112
21	240	201	53.1	750	109
20	234	196	52.4	730	106

低硬度区换算（布氏 / 维氏，退火与正火钢）

HB（布氏）	HV（维氏）	HRB	近似抗拉强度 MPa	典型状态
600	618	—	2070	Hardened high-carbon steel
550	562	—	1900	Hardened alloy steel
500	510	—	1720	Hardened medium-carbon steel
450	457	—	1550	Quenched & tempered (low temper)
400	404	—	1380	Q&T alloy steel
350	354	(38.8 HRC)	1210	Q&T medium-carbon steel
300	302	(31.7 HRC)	1040	Normalised alloy steel
275	277	100	950	Hot-rolled alloy steel
250	253	98	860	Normalised medium-carbon
225	228	96	770	Hot-rolled medium-carbon
200	202	92	690	Annealed alloy steel
180	183	88	620	Normalised mild steel
160	162	83	550	Hot-rolled mild steel
140	142	77	480	Annealed mild steel
120	121	68	410	Low-carbon steel (EN3)
100	101	56	340	Annealed low-carbon

硬度试验方法选择

试验方法	压头	载荷	适用	局限
HRC (Rockwell C)	120° diamond cone	150 kgf	Hardened steels (20-70 HRC)	Not for thin sections (<1.5mm) or case-hardened below 0.6mm depth
HRB (Rockwell B)	1/16" steel ball	100 kgf	Soft steels, brass, aluminium	Range 0-100 HRB only. Not for hardened steels.
HV (Vickers)	136° diamond pyramid	1-120 kgf	All metals, any hardness. Research. Thin layers.	Requires surface preparation. Slow. Indent must be measured optically.
HB (Brinell)	10mm carbide ball	3000 kgf (steel)	Castings, forgings, raw stock	Large indent. Not for hardened steels (>450 HB). Requires flat surface.
HK (Knoop)	Elongated diamond	0.025-1 kgf	Brittle materials, thin coatings, ceramics	Very small indent. Lab use only.
Leeb (portable)	Rebound	Impact body	Field testing, large components, installed equipment	Surface condition critical. Minimum mass 5kg. Conversion required.

碳素钢与合金钢（BS EN 牌号）

牌号	BS EN / UNS	奥氏体化温度（°C）	淬火	回火范围（°C）	可达硬度 HRC	备注
EN8	080M40	830-860	Water / Oil	540-680	23-32	Medium carbon. Normalise 830-860°C.
EN9	070M55	810-840	Water / Oil	540-680	28-38	Springs, hand tools. Higher carbon than EN8.
EN16	605M36	830-860	Oil	550-660	28-36	Mn-Mo alloy. Good through-hardening.
EN19	709M40	830-860	Oil	540-680	28-38	Cr-Mo alloy. Widely used. Equiv. AISI 4140.
EN24	817M40	820-850	Oil	540-660	28-42	Ni-Cr-Mo. Excellent toughness. Equiv. AISI 4340.
EN26	826M40	820-850	Oil	540-660	30-44	Higher Ni version of EN24. Heavy sections.
EN30B	835M30	810-840	Oil	540-660	30-40	4.25% Ni-Cr-Mo. Aircraft/heavy duty.
EN31	535A99	820-850	Oil	150-250	58-65	1% Cr bearing steel. Equiv. AISI 52100.
EN36	655M13	800-830	Oil	150-200	58-63	Case hardening. Carburise 900-930°C.
EN40B	722M24	900-940	Oil / Air	550-680	30-36	Nitriding steel (3% Cr-Mo-V). Nitride at 500-530°C.

工具钢

牌号	AISI	奥氏体化温度（°C）	淬火	回火范围（°C）	可达硬度 HRC	备注
H13	H13	1010-1040	Air / Gas	540-650	44-52	Hot-work die steel. Double/triple temper. Secondary hardening peak ~540°C.
D2	D2	1000-1025	Air	200-540	58-62	High-Cr cold-work. Deep freeze -80°C recommended. Anneal 870°C.
M2	M2	1190-1230	Oil / Salt / Gas	540-580	63-66	HSS. Triple temper essential. Preheat 450°C then 850°C. Critical soak time.
M42	M42	1165-1190	Oil / Salt / Gas	540-570	67-70	Super HSS (8% Co). Triple temper. Highest attainable hardness of HSS grades.
A2	A2	940-970	Air	175-540	57-62	Air-hardening cold-work. Good dimensional stability.
O1	O1	790-815	Oil	175-315	57-62	Oil-hardening. Low aust. temp. Good for fine detail. Anneal 760°C.
S7	S7	925-955	Air / Oil	200-620	50-58	Shock-resistant. Impact tools. Good toughness at high hardness.

不锈钢

牌号	类型	处理	温度（°C）	冷却	硬度	备注
304	Austenitic	Solution anneal	1010-1120	Rapid cool (water)	~80 HRB	Cannot be hardened by heat treatment. Avoid 425-860°C (sensitisation).
316	Austenitic	Solution anneal	1010-1120	Rapid cool (water)	~80 HRB	Mo addition for pitting resistance. Same sensitisation risk as 304.
17-4PH	PH Martensitic	Solution treat	1040±15	Air cool to <32°C	See below	Must cool to room temp before ageing.
		H900 age	480°C / 1hr	Air	40-44 HRC	Maximum strength condition.
		H1025 age	550°C / 4hr	Air	34-38 HRC	Optimum strength + toughness.
		H1075 age	580°C / 4hr	Air	31-35 HRC	Good toughness, moderate strength.
410	Martensitic	Harden	925-1010	Oil / Air	38-43 HRC	General-purpose martensitic. Temper immediately.
420	Martensitic	Harden	980-1040	Oil / Air	50-55 HRC	Higher carbon than 410. Cutlery, surgical.
440C	Martensitic	Harden	1010-1065	Oil / Air	58-60 HRC	Highest hardness stainless. Bearings, valves. Deep freeze recommended.

铝合金

牌号	固溶温度（°C）	淬火	时效温度（°C）	时效时间	状态	备注
2024	490-500	Water (max 40°C)	190-195	8-12 hr	T6	Al-Cu. Aircraft. Natural ageing T4 = room temp 96hr. Quench within 7s.
6061	527-532	Water	175-180	8-10 hr	T6	Al-Mg-Si. General structural. T4 natural age 96hr at RT.
6082	525-540	Water	170-180	8-10 hr	T6	Common UK structural alloy. Similar to 6061 but higher Si.
7075	465-480	Water (max 40°C)	120-130	24 hr	T6	Al-Zn-Mg-Cu. High strength aerospace. T73 for SCC resistance: 107°C/6hr + 177°C/8hr.

镍基与钴基合金

合金	UNS	处理	温度（°C）	冷却	备注
Inconel 600	N06600	Anneal	980-1050	Air or water	Stress relief 870-900°C / 1hr. No age hardening.
Inconel 625	N06625	Anneal	1040-1150	Air or water	Solid-solution strengthened. Extended service below 650°C.
Inconel 718	N07718	Solution treat	954-982	Air cool	Most common Ni superalloy.
		Age (AMS 5663)	718°C/8hr + 621°C/8hr	Air	Standard double-age. 40-44 HRC.
Inconel X-750	N07750	Solution treat	1150	Air cool
		Age	705°C/20hr	Air	Springs, fasteners. 35-40 HRC.
Waspaloy	N07001	Solution treat	1010-1040	Air or oil
		Age	845°C/4hr + 760°C/16hr	Air	Aerospace turbine discs.
Hastelloy X	N06002	Solution anneal	1150-1175	Rapid air cool	Combustion cans, afterburners. Non-age-hardenable.
Stellite 6	R30006	Stress relief	540-650	Furnace cool	Co-Cr-W hardfacing alloy. Cannot be heat treated for hardness. 38-44 HRC as-cast.

钛合金

合金	类型	处理	温度（°C）	冷却	备注
CP Ti Gr 2	Alpha	Stress relief	480-595	Air	Cannot age-harden. Most common commercially pure grade.
Ti-6Al-4V (Gr 5)	Alpha-Beta	Anneal	700-790	Air or furnace	Most common Ti alloy.
		Solution treat	925-970	Water quench	Must be below beta transus (995°C).
		Age	480-595 / 4-8hr	Air	Achieves 36-42 HRC. Aerospace fasteners, surgical.
Ti-6Al-2Sn-4Zr-2Mo	Near-alpha	Anneal	900	Air	High-temp creep resistant. Compressor discs.

表面硬化（渗碳）速查

工艺	温度（°C）	介质	渗层深度	表面硬度	典型钢种
Gas carburising	900-940	Endothermic gas + enrichment (CH4 or C3H8)	0.5-2.5mm	58-63 HRC	EN36, 8620, 9310, 16MnCr5
Vacuum carburising (LPC)	920-1050	Acetylene (C2H2) at 5-15 mbar	0.3-3.0mm	58-63 HRC	Same + tool steels
Carbonitriding	820-870	Endothermic gas + ammonia	0.1-0.75mm	58-62 HRC	Low-carbon steels, EN8
Gas nitriding	500-530	Ammonia (NH3)	0.1-0.6mm	65-72 HRC (HV 800-1200)	EN40B, EN41B, Nitralloy, H13, 4140
Plasma (ion) nitriding	350-580	N2/H2 glow discharge	0.05-0.5mm	65-72 HRC	All nitriding steels + stainless + Ti
Nitrocarburising (Tenifer/QPQ)	560-580	Salt bath or gas (NH3 + CO2)	10-25μm compound layer	55-65 HRC	Mild steel, cast iron, stainless
Induction hardening	850-1050	Electromagnetic heating + water/polymer quench	0.5-10mm	50-62 HRC	EN8, EN19, EN24, 4140, 4340
Flame hardening	830-900	Oxy-fuel flame + water quench	1.0-6.0mm	50-60 HRC	EN8, EN9, cast iron (min 0.4%C)

热电偶类型与精度

类型	正极 / 负极材质	量程（°C）	1 级精度	2 级精度	IEC 线色（+/-）	典型应用
K	Ni-Cr / Ni-Al	-200 to +1260	±1.5°C or ±0.4%	±2.5°C or ±0.75%	Green (+) / White (-)	General purpose, furnaces, kilns. Most common industrial type.
J	Fe / Cu-Ni	-210 to +760	±1.5°C or ±0.4%	±2.5°C or ±0.75%	Black (+) / White (-)	Vacuum, reducing atmospheres. Avoid oxidising above 500°C.
N	Ni-Cr-Si / Ni-Si	-270 to +1300	±1.5°C or ±0.4%	±2.5°C or ±0.75%	Pink (+) / White (-)	Higher stability than K at elevated temps. Resists green rot.
R	Pt-13%Rh / Pt	0 to +1600	±1.0°C or ±[1+0.003(t-1100)]	±1.5°C or ±0.25%	Orange (+) / White (-)	High-temp precision, glass, ceramics, semiconductor.
S	Pt-10%Rh / Pt	0 to +1600	±1.0°C or ±[1+0.003(t-1100)]	±1.5°C or ±0.25%	Orange (+) / White (-)	Reference standard, high-temp precision, laboratory.
B	Pt-30%Rh / Pt-6%Rh	+200 to +1800	±0.25% of t	±0.5% of t	Grey (+) / White (-)	Very high temp. No CJC needed below 50°C. Glass, sintering.
T	Cu / Cu-Ni	-270 to +370	±0.5°C or ±0.4%	±1.0°C or ±0.75%	Brown (+) / White (-)	Cryogenics, food, HVAC. Good in moist environments.
E	Ni-Cr / Cu-Ni	-270 to +870	±1.5°C or ±0.4%	±2.5°C or ±0.75%	Violet (+) / White (-)	Highest output of base metal types. Cryogenic to moderate heat.
C (W5Re/W26Re)	W-5%Re / W-26%Re	0 to +2315	±1% of t	±1% of t	White (+) / White (-)	Vacuum furnaces, hydrogen atmospheres. Very high temp. Brittle.

热电偶线色标准（IEC / ANSI）

类型	IEC 60584 正极	IEC 60584 负极	IEC 护套	ANSI/ASTM 正极	ANSI/ASTM 负极	ANSI 护套
K	Green	White	Green	Yellow	Red	Yellow
J	Black	White	Black	White	Red	Black
N	Pink	White	Pink	Orange	Red	Orange
T	Brown	White	Brown	Blue	Red	Blue
E	Violet	White	Violet	Purple	Red	Purple
R	Orange	White	Orange	Black	Red	Green
S	Orange	White	Orange	Black	Red	Green
B	Grey	White	Grey	Grey	Red	Grey

热电偶毫伏输出参考（0°C 冷端）

温度（°C）	K 型	J 型	N 型	T 型	E 型	R 型	S 型
-200	-5.891	—	-3.990	-5.603	-8.825	—	—
-100	-3.554	-4.633	-2.407	-3.379	-5.237	—	—
0	0.000	0.000	0.000	0.000	0.000	0.000	0.000
100	4.096	5.269	2.774	4.279	6.319	0.647	0.646
200	8.138	10.779	5.913	9.288	13.421	1.469	1.441
300	12.209	16.327	9.341	14.862	21.036	2.401	2.323
400	16.397	21.848	12.974	—	28.946	3.408	3.259
500	20.644	27.393	16.748	—	37.005	4.471	4.233
600	24.905	33.102	20.613	—	45.093	5.583	5.239
700	29.129	39.132	24.527	—	53.112	6.743	6.275
800	33.275	—	28.455	—	61.017	7.950	7.345
900	37.326	—	32.371	—	—	9.205	8.449
1000	41.276	—	36.256	—	—	10.506	9.587
1100	45.119	—	40.087	—	—	11.850	10.757
1200	48.838	—	43.846	—	—	13.228	11.951
1300	—	—	47.513	—	—	14.629	13.159
1400	—	—	—	—	—	16.040	14.373
1500	—	—	—	—	—	17.445	15.582
1600	—	—	—	—	—	18.842	16.777

热电偶套管材质兼容性

套管材质	最高温度（°C）	气氛兼容性	备注
Inconel 600	1150	Oxidising, neutral, vacuum. Limited in sulphur/carburising.	Most common industrial sheath. Good general-purpose.
Inconel 601	1200	Oxidising, neutral. Better than 600 at high temp.	Higher Al content improves oxidation resistance.
316 SS	870	Oxidising, neutral, mildly reducing.	Lower cost. Suitable for moderate temperatures.
310 SS	1050	Oxidising, neutral. Carburisation resistant.	Good for carburising atmospheres.
Kanthal (FeCrAl)	1300	Oxidising, neutral. Do NOT use in vacuum.	Good for high-temp oxidising service.
Mullite (ceramic)	1600	All except HF and strong alkali.	Porous – not gas-tight. Use as outer protection tube.
Alumina (99.7%)	1800	All except HF.	Premium ceramic. Used for noble metal TC protection.
Silicon carbide	1600	Oxidising, neutral, vacuum.	Excellent thermal shock resistance. Molten metal protection.
Molybdenum	1700	Vacuum and hydrogen only.	Vacuum furnace use. Oxidises rapidly in air above 400°C.
Tantalum	2200	Vacuum only.	Specialist ultra-high-temp vacuum applications.

热电偶套管规格

外径 mm	外径 in	典型用途	标准卡套接头	备注
1.5	0.060"	MIMS (mineral insulated)	1/16" Swagelok	Fast response. Fragile. Bend radius ≥5× OD.
3.0	0.118" (1/8")	MIMS, thin-wall thermowells	1/8" Swagelok	Good response. Standard for TUS probes.
4.5	0.177" (3/16")	General industrial	3/16" Swagelok	Common UK industrial size. Good balance of response and strength.
6.0	0.236" (1/4")	Heavy-duty, thermowells	1/4" Swagelok / BSP adaptor	Standard for permanent control TCs. Robust.
8.0	0.315" (5/16")	Protection tubes, heavy duty	5/16" Swagelok / 1/4" BSP gland	Thick wall for aggressive atmospheres. Slower response.
10.0	0.394" (3/8")	Ceramic protection tubes	3/8" gland / bayonet	Mullite/alumina outer tubes for very high temp.

常用温度参考点

°C	°F	意义	°C	°F	意义
0	32	Water freezes	727	1341	Steel eutectoid (A1)
100	212	Water boils	768	1414	Iron Curie point
150	302	Low temper	843	1550	Typical aust. temp (steel)
200	392	Stress relief (Al)	912	1674	Iron A3 (pure Fe)
232	450	Sn melting point	1010	1850	SS solution anneal
327	621	Pb melting point	1064	1947	Au melting point
419	786	Zn melting point	1083	1981	Cu melting point
449	840	Temper embrittlement zone start	1148	2098	Fe-C eutectic
500	932	Typical nitriding temp	1455	2651	Ni melting point
550	1022	H13 secondary hardening peak	1538	2800	Pure Fe melting point
593	1100	Common stress relief (steel)	1668	3034	Ti melting point
660	1220	Al melting point	1769	3216	Pt melting point

AMS 2750 炉温等级

等级	均匀性（°C）	均匀性（°F）	典型应用
1	±3°C	±5°F	Aluminium solution treatment, precipitation hardening (tight tolerance)
2	±6°C	±10°F	Aerospace hardening & tempering, nitriding, carburising
3	±8°C	±15°F	Vacuum heat treatment, brazing
4	±14°C	±25°F	General hardening & tempering
5	±28°C	±50°F	Stress relief, normalising, annealing
6	±56°C	±100°F	Tempering (non-critical), pre-/post-weld heat treatment

SAT / TUS 周期要求（AMS 2750F）

试验	初始	例行	修复后	备注
System Accuracy Test (SAT)	Before first use	Quarterly (3 months max)	Before next production run	Compares control/recording instruments against calibrated test instrument. Must pass ±1.0°C or ±0.4% of reading.
Temperature Uniformity Survey (TUS)	Before first use	Monthly to annually*	Before next production run	*Frequency based on test reduction criteria. Start monthly, can extend to semi-annual or annual with consecutive passes.

气体性质（STP：0°C、1 atm）

STP（0°C、1 atm）性质；LEL/UEL 为空气中体积百分比。

气体	公式	分子量	密度 kg/m³	Cp kJ/kg·K	爆炸下限 %	爆炸上限 %	自燃点（°C）	最高使用（°C）	职业接触限值 ppm
Nitrogen	N2	28.01	1.250	1.040	—	—	—	—	Asphyxiant
Hydrogen	H2	2.016	0.090	14.30	4.0	75.0	500	~1100	Asphyxiant
Argon	Ar	39.95	1.784	0.520	—	—	—	—	Asphyxiant
Carbon Monoxide	CO	28.01	1.250	1.040	12.5	74.0	609	—	20 TWA
Carbon Dioxide	CO2	44.01	1.977	0.844	—	—	—	—	5000 TWA
Methane	CH4	16.04	0.717	2.220	5.0	15.0	537	~700	1000 TWA
Propane	C3H8	44.10	2.010	1.670	2.1	9.5	470	~700	1000 TWA
Ammonia	NH3	17.03	0.769	2.060	15.0	28.0	651	~550	25 TWA
Helium	He	4.003	0.179	5.193	—	—	—	—	Asphyxiant
Endothermic Gas	~20%CO, 40%H2, 40%N2	~18	~0.80	~1.3	~5	~40	~500	~1100	See CO
Exothermic Gas	~1.5%CO, 1%H2, ~87%N2	~28	~1.24	~1.05	—	—	—	~1100	See CO

其他炉用气体

气体	公式	关键性质	炉子应用	危害
Acetylene	C2H2	MW 26.04, SG 0.91, LEL 2.5%, UEL 81%, auto-ign 305°C	Vacuum carburising (LPC) carrier gas. Oxy-acetylene cutting/welding.	Extremely wide flammable range. Unstable above 1.5 bar gauge (can decompose explosively). Store below 15°C.
Butane	C4H10	MW 58.12, SG 2.08, LEL 1.8%, UEL 8.4%, auto-ign 405°C	Portable heating, brazing. Not common in process furnaces.	Heavier than air (SG 2.08). Pools in low areas. Narcotic at high concentration.
Dissociated ammonia	75% H2 + 25% N2	MW ~8.5, SG ~0.30, LEL ~6%, highly reducing	Bright annealing of copper, brazing, sintering. Low cost H2 source.	Residual NH3 may be present. Flammable. Monitor both NH3 and %LEL.
Forming gas	5-10% H2 in N2	MW ~26.5, mildly reducing, below LEL of H2	Brazing, sintering, semiconductor processing. Below explosive limit.	Not classified as flammable below 5.7% H2. Simple asphyxiant.
Cracked methanol	67% H2 + 33% CO	MW ~12, SG ~0.42, flammable, toxic (CO)	Bright hardening, carburising, copper brazing. Carbon-neutral atmosphere.	Highly toxic (CO) and flammable. Methanol itself is toxic (TWA 200 ppm).

吸热气氛露点—碳势对应（925°C）

吸热气氛 925°C 下的露点—碳势对应关系。

露点（°C）	碳势（%C）	应用
+10	0.30	Decarburisation zone. Too wet for most work.
+5	0.35	Low-carbon neutral hardening.
0	0.40	Neutral for 0.40%C steels (e.g., EN19).
-5	0.50	Neutral for 0.50%C steels.
-10	0.60	Slight carburising for most steels.
-15	0.70	Light carburising.
-20	0.80	Typical carburising carbon potential.
-25	0.90	High carburising. Risk of carbide network.
-30	1.00	Boost phase of carburising cycle.
-40	1.10	Maximum practical. Soot deposition risk.

职业接触限值（EH40/2005）

职业接触限值依据 EH40/2005（英国 HSE）；IDLH 依据 NIOSH。报警设定为行业惯例（一级 50% LTEL、二级 LTEL）。

气体	长期接触限值（8h）	短时接触限值（15min）	立即危险浓度	一级报警	二级报警	备注
CO (Carbon Monoxide)	20 ppm	100 ppm	1200 ppm	10 ppm	20 ppm	Odourless. Combines with haemoglobin (COHb). 400 ppm = lethal in 3hr.
CO2 (Carbon Dioxide)	5000 ppm	15,000 ppm	40,000 ppm	2500 ppm	5000 ppm	Heavier than air. Displaces O2. 10% = unconsciousness in 1 min.
NH3 (Ammonia)	25 ppm	35 ppm	300 ppm	12 ppm	25 ppm	Pungent odour (detectable at 5 ppm). Corrosive to eyes/lungs. Lighter than air.
H2S (Hydrogen Sulphide)	5 ppm	10 ppm	100 ppm	2.5 ppm	5 ppm	Rotten egg smell (olfactory fatigue above 100 ppm). Extremely toxic.
SO2 (Sulphur Dioxide)	0.5 ppm	1 ppm	100 ppm	0.25 ppm	0.5 ppm	Sharp pungent odour. Severe respiratory irritant. Heavier than air.
NO2 (Nitrogen Dioxide)	0.5 ppm	1 ppm	20 ppm	0.25 ppm	0.5 ppm	Brown/orange gas. Delayed pulmonary oedema. Product of combustion.
HCN (Hydrogen Cyanide)	0.9 ppm	4.5 ppm (ceiling)	50 ppm	0.5 ppm	0.9 ppm	Faint almond odour (40% of people cannot detect). Rapidly fatal above 50 ppm. Used in carbonitriding.
CH4 (Methane)	1000 ppm	—	—	10% LEL (5000 ppm)	20% LEL (10,000 ppm)	Simple asphyxiant. Monitor as %LEL in confined spaces. Lighter than air.
H2 (Hydrogen)	—	—	—	10% LEL (4000 ppm)	20% LEL (8000 ppm)	Simple asphyxiant. Monitor as %LEL. Invisible flame. Much lighter than air.
O2 (Oxygen) – deficient	<19.5% = deficient	—	<16% impaired	19.5%	18.0%	Normal air = 20.9%. Below 16% = impaired judgement. Below 10% = unconsciousness. Below 6% = death.
O2 (Oxygen) – enriched	>23.5% = enriched	—	—	23.0%	23.5%	Greatly increases fire risk. Clothing can spontaneously ignite. No smoking/naked flame.

气体检测传感器类型

传感器类型	检测对象	量程	寿命	备注
Electrochemical cell	CO, H2S, SO2, NO2, O2, NH3	0-500 ppm (toxic), 0-25% (O2)	2-3 years	Gas-specific. Requires regular calibration. Cross-sensitivity to H2 on some CO cells.
Catalytic bead (pellistor)	Combustible gases (%LEL)	0-100% LEL	3-5 years	Non-selective (responds to any combustible gas). Poisoned by silicones, H2S, lead.
Infrared (NDIR)	CO2, CH4, hydrocarbons	0-100% by volume	5-10 years	Not poisoned. Gas-selective. Higher cost. Cannot detect H2 (no IR absorption).
Photoionisation (PID)	VOCs, organic vapours	0.1-10,000 ppm	2-3 years (lamp)	Broad-spectrum organic detection. Lamp energy determines detectable species.
Semiconductor (MOS)	Combustibles, some toxic	1-1000 ppm	5+ years	Low cost. Poor selectivity. Drift. Used in domestic CO alarms.

压力换算表

mbar	Pa	Torr（mmHg）	atm	psi	微米汞柱
1013.25	101,325	760	1.000	14.696	760,000
1000	100,000	750.06	0.987	14.504	750,060
100	10,000	75.01	0.0987	1.450	75,006
10	1,000	7.501	9.87×10-3	0.145	7,501
1	100	0.7501	9.87×10-4	0.0145	750.1
0.1	10	0.0750	9.87×10-5	1.45×10-3	75.01
0.01	1	7.50×10-3	9.87×10-6	1.45×10-4	7.501
0.001	0.1	7.50×10-4	9.87×10-7	1.45×10-5	0.750
1×10-4	0.01	7.50×10-5	9.87×10-8	1.45×10-6	0.075
1×10-7	1×10-5	7.50×10-8	9.87×10-11	1.45×10-9	7.5×10-5

真空度分级

量程	压力（mbar）	压力（Pa）	典型泵型
Rough Vacuum	1013 to 1	105 to 102	Rotary vane, scroll, roots (booster)
Fine (Medium) Vacuum	1 to 10-3	102 to 10-1	Roots + rotary backing, oil diffusion
High Vacuum	10-3 to 10-7	10-1 to 10-5	Diffusion, turbo-molecular, cryo
Ultra-High Vacuum	<10-7	<10-5	Ion, getter, turbo + bake-out

典型工艺真空度

工艺	典型压力（mbar）	典型压力（Torr）	备注
Vacuum Hardening	10-2 to 10-1	10-2 to 7.5×10-2	N2 backfill for gas quench. Partial pressure N2 to reduce Cr evaporation.
Vacuum Tempering	10-1 to 1	7.5×10-2 to 0.75	Lower vacuum requirement. Convection heating may be used.
Vacuum Brazing (Ni)	10-4 to 10-3	10-4 to 7.5×10-4	Must dissociate surface oxides. Higher vacuum for Ti/Zr alloys.
Vacuum Brazing (Al)	10-5 to 10-4	10-5 to 7.5×10-5	Very clean conditions required. Mg getter used to reduce oxides.
Vacuum Sintering	10-3 to 10-2	10-3 to 7.5×10-3	PM parts. May use H2 partial pressure for oxide reduction.
Vacuum Carburising (LPC)	5-15	3.75-11.25	Acetylene (C2H2) carrier gas. Pulse/boost-diffuse cycles.
Vacuum Annealing (SS)	10-3 to 10-2	10-3 to 7.5×10-3	Bright annealing of stainless. Partial pressure Ar acceptable.
Electron Beam Welding	10-4 to 10-3	10-4 to 7.5×10-4	Beam requires high vacuum for electron mean free path.
CVD / PVD Coating	10-4 to 10	10-4 to 7.5	Wide range depending on process. PVD typically 10-3-10-1 mbar.
Degassing (VD/VOD)	0.5-5	0.375-3.75	Molten steel degassing. Removes H, N, O. Requires large pumping capacity.

真空泵选型

泵型	极限压力（mbar）	抽速范围	优点	局限
Rotary vane (oil-sealed)	~10-3	2-600 m³/hr	Reliable, low cost, good for rough vacuum and backing	Oil backstreaming, maintenance, oil mist disposal
Scroll (dry)	~10-2	5-50 m³/hr	Oil-free, clean, low maintenance	Lower ultimate vacuum, limited size range
Roots blower (booster)	~10-3 (with backing)	100-12,000 m³/hr	Very high pumping speed, good for large chambers	Must have backing pump. Cannot start against atmosphere.
Oil diffusion	~10-8	100-50,000 l/s	High speed, no moving parts, reliable, proven technology	Oil backstreaming, long warm-up, requires LN2 baffle
Turbomolecular	~10-10	50-5,000 l/s	Very clean, fast start, no oil, UHV capable	Expensive, bearing maintenance, fragile to particles
Cryopump	~10-10	500-50,000 l/s	Very clean, highest pumping speed, UHV	Must regenerate periodically, helium compressor noise

真空计选型

真空计类型	量程（mbar）	与气体种类有关？	备注
Bourdon / diaphragm	Atm to ~1	No	Direct mechanical pressure measurement.
Capacitance manometer	1000 to 10-4	No	Most accurate. Absolute or differential. Expensive.
Pirani (thermal)	1000 to 10-4	Yes	Common, low cost. Calibrated for N2/air. Reads wrong for other gases.
Thermocouple gauge	10 to 10-3	Yes	Similar to Pirani. Lower accuracy. Very robust.
Penning (cold cathode)	10-2 to 10-8	Yes	No filament (robust). Can take time to strike. Common on furnaces.
Bayard-Alpert (hot cathode)	10-3 to 10-10	Yes	Most accurate for high vacuum. Fragile filament. Burns out in air.

淬火烈度 H 值（Grossmann）

Grossmann 淬火烈度因子 H 反映相对换热强度，H 越大越剧烈；数值针对钢件。

淬火介质	状态	H 值（in⁻¹）	700°C 近似冷速（°C/s）	备注
Brine (10% NaCl)	Agitated	5.0	~300	Most severe liquid quench. Risk of distortion/cracking.
Brine (10% NaCl)	Still	2.0	~150	Salt film can cause uneven cooling.
Water	Vigorous agitation	4.0	~250	Common for plain carbon steels.
Water	Good agitation	1.5	~120	Standard water quench.
Water	Moderate agitation	1.0	~80	—
Water	Still	0.25	~30	Vapour blanket reduces cooling. Avoid for critical work.
Caustic soda (10% NaOH)	Agitated	2.0	~150	Breaks vapour blanket effectively. Corrosive – PPE essential.
Fast oil (quench oil)	Good agitation	0.8-1.0	~60-80	Houghton Quench K, Park AAA. Flash point >170°C.
Conventional oil	Good agitation	0.5-0.7	~40-55	General purpose mineral quench oil.
Conventional oil	Still	0.25-0.30	~20-25	Vapour phase can last several seconds.
Marquench oil	120-180°C	0.2-0.4	~15-30	Hot oil. Reduces distortion. For martempering.
Polymer (PAG 10-25%)	Agitated	0.5-2.0	~30-150	Adjustable severity by concentration. Environmentally preferred.
Salt bath (molten)	200-400°C	0.5-2.0	~30-150	Marquenching / austempering. Very uniform cooling.
Nitrogen gas	2 bar, high velocity	0.15-0.25	~10-18	Vacuum furnace gas quench. Clean, no residue.
Nitrogen gas	6 bar, high velocity	0.4-0.6	~30-45	High-pressure gas quench (HPGQ). Approaching oil severity.
Nitrogen gas	10 bar, high velocity	0.6-0.8	~45-60	Very high pressure. Specialist equipment required.
Helium gas	6 bar, high velocity	0.6-0.8	~45-60	Better thermal conductivity than N2. Expensive. Recycling recommended.
Hydrogen gas	6 bar	0.8-1.2	~60-90	Best gas quench medium. Explosive risk – specialist furnace required.
Still air	Room temp	0.02	~2	Air-hardening steels only (A2, D2, H13, high-alloy).
Forced air / fan	High velocity	0.05-0.10	~5-8	Fan cool. Suitable for air-hardening tool steels.

淬火油维护检查单

试验	频次	限值	超标处置
Flash point	Monthly	>170°C (fast oil), >160°C (conventional)	Replace oil. Do not top up.
Viscosity (40°C)	Monthly	Per manufacturer spec ±20%	Filter or replace. Indicates contamination or degradation.
Water content	Weekly	<0.05% (500 ppm)	Remove water source. Centrifuge or replace. Water causes foaming and fire risk.
Total acid number (TAN)	Quarterly	<0.5 mg KOH/g	Indicates oxidation. Replace or re-refine.
Carbon residue	Quarterly	<0.15% (Conradson)	Indicates thermal cracking. Filter or replace.
Cooling curve test	Semi-annual	Per ISO 9950 / ASTM D6200	Compare to new oil baseline. Replace if cooling rate drops >15%.
Operating temperature	Continuous	60-80°C (conventional), 120-180°C (marquench)	Check cooler, heater, and circulation pump.

聚合物淬火液浓度指南

浓度（%）	近似 H 值	等效于	典型用途
5-8%	1.5-2.0	Vigorous water agitation	Plain carbon steels, large sections
10-15%	0.8-1.2	Fast quench oil (agitated)	Alloy steels, general hardening
15-25%	0.5-0.8	Conventional oil	Crack-sensitive parts, thin sections, complex geometry
25-35%	0.3-0.5	Slow oil / marquench	Air-hardening steels requiring slight acceleration

陶瓷纤维制品

材料	分类温度（°C）	连续使用（°C）	k@400°C	k@800°C	k@1000°C	密度 kg/m³
Standard Grade (RCF)	1260	1050-1100	0.08	0.16	0.23	96-128
High Purity (HP)	1260	1100	0.08	0.15	0.21	96-128
AES (Alkaline Earth Silicate)	1200	1000	0.07	0.15	0.22	96-128
High Alumina (HA)	1400	1250	0.09	0.17	0.24	96-128
Polycrystalline (PCW)	1600	1500	0.10	0.19	0.26	160-192
Superwool (bio-soluble)	1300	1100	0.07	0.14	0.20	96-128

隔热耐火砖（IFB）

IFB 牌号	最高使用（°C）	密度 kg/m³	k@400°C	k@800°C	常温耐压强度 MPa
Grade 23 (K-23)	1260	510-580	0.13	0.17	1.4
Grade 25 (K-25)	1400	540-600	0.14	0.18	1.5
Grade 26 (K-26)	1430	580-640	0.16	0.20	2.0
Grade 28 (K-28)	1540	650-720	0.19	0.24	2.5
Grade 30 (K-30)	1650	770-850	0.23	0.29	3.0

致密耐火砖与浇注料

材料	最高使用（°C）	密度 kg/m³	k@400°C	k@1000°C	备注
Fireclay brick	1450	1900-2100	0.95	1.10	General purpose. 30-45% Al2O3.
High alumina brick (60%)	1600	2200-2400	1.40	1.50	Abrasion resistant. Slag contact.
High alumina brick (90%)	1800	2800-3100	2.50	2.80	Very high duty. Kiln furniture.
Silica brick	1700	1800-1900	1.20	1.50	Coke ovens, glass tanks. Spalling below 600°C.
Magnesia brick	1800	2800-3000	4.00	3.00	Basic lining. Steelmaking converters. Hydrates in moist air.
SiC brick	1600	2500-2700	12.00	8.00	Excellent thermal shock resistance. Kiln shelves.
Low-cement castable (LCC)	1500-1700	2200-2500	1.20	1.40	Monolithic lining. Requires controlled dry-out. 4-8% CaO.
Insulating castable	1200-1400	800-1200	0.25	0.35	Lightweight backing. Vermiculite/perlite aggregate.

其他隔热材料

材料	最高使用（°C）	k@平均温度	备注
Calcium silicate board	1000	0.07-0.10 (at 200°C)	Structural insulation. Non-combustible. Asbestos-free grades available.
Microporous insulation	1000	0.02-0.03 (at 400°C)	Promat, Microtherm. 2-3× better than ceramic fibre. Expensive. Fragile.
Mineral wool (stone)	750	0.04-0.07 (at 200°C)	External cladding insulation. Rockwool, Isover. Not for hot-face use.
Vermiculite board	1100	0.10-0.15 (at 400°C)	Fire protection. Backing insulation. Good compressive strength.
Graphite felt	2200 (inert/vacuum)	0.15-0.40 (at 1000°C)	Vacuum furnace hot zones. Burns in air above 400°C.
Molybdenum shields	1700 (vacuum)	Radiation shields	Multiple layer radiation shielding in vacuum hot zones. Typically 3-5 layers.

常用 BSP 螺纹（炉上 / 燃气）

BSP 规格	大径 mm	每英寸牙数	底孔 mm	典型用途
1/8" BSP	9.728	28	8.55	Instrument connections, pressure tappings
1/4" BSP	13.157	19	11.45	Thermocouple glands, small valves, pressure gauges
3/8" BSP	16.662	19	14.95	Pilot gas, instrument air
1/2" BSP	20.955	14	18.60	Small burner gas connections, drain cocks
3/4" BSP	26.441	14	24.10	Process gas, atmosphere inlet
1" BSP	33.249	11	30.30	Main gas supply, atmosphere lines
1-1/4" BSP	41.910	11	38.95	Larger burner connections
1-1/2" BSP	47.803	11	44.85	Main gas headers
2" BSP	59.614	11	56.65	Large gas mains, exhaust

BSP 与 NPT 对比

特性	BSP（英标管螺纹）	NPT（美标锥管螺纹）
Thread angle	55° (Whitworth)	60°
Parallel version	BSPP (G) – uses washer/O-ring seal	NPS (straight) – not common for sealing
Taper version	BSPT (R) – 1:16 taper	NPT – 1:16 taper
Sealing method	BSPP: washer/bond. BSPT: thread taper + PTFE	Thread taper + PTFE tape
Standard	BS EN ISO 228 (parallel), BS EN 10226 (taper)	ASME B1.20.1
Common in	UK, Europe, Asia, Commonwealth	USA, Canada

燃气系统法兰等级（BS EN 1092-1）

PN 等级	近似 psi	炉上典型应用	垫片类型
PN6	87	Low-pressure gas, atmosphere lines, vent stacks	Flat ring (non-metallic)
PN16	232	Standard gas supply, most furnace gas connections	Flat ring or spiral wound
PN25	363	Medium-pressure gas, compressed air	Spiral wound
PN40	580	High-pressure gas, hydraulic quench systems	Spiral wound or ring joint

钢管公称口径与外径（BS EN 10255 / ASTM A106）

公称口径 in	公称口径 DN mm	外径 mm	壁厚-薄 mm	壁厚-中 mm	壁厚-厚 mm
1/4"	DN8	13.5	1.8	2.3	3.0
3/8"	DN10	17.2	1.8	2.3	3.0
1/2"	DN15	21.3	2.0	2.6	3.25
3/4"	DN20	26.9	2.0	2.6	3.25
1"	DN25	33.7	2.6	3.25	4.05
1-1/4"	DN32	42.4	2.6	3.25	4.05
1-1/2"	DN40	48.3	2.6	3.25	4.05
2"	DN50	60.3	2.9	3.65	4.50
2-1/2"	DN65	76.1	2.9	3.65	4.50
3"	DN80	88.9	3.2	4.05	5.0
4"	DN100	114.3	3.6	4.50	5.40
5"	DN125	139.7	3.6	4.85	5.40
6"	DN150	168.3	4.0	4.85	5.40

公制 / 英制管径与壁厚对照

燃气管路、液压管路与冷却水系统常用管径。

DN	NPS in	外径 mm	Sch10 壁厚/内径 mm	Sch40 壁厚/内径 mm	Sch80 壁厚/内径 mm
8	¼"	13.72	1.65 / 10.42	2.24 / 9.24	3.02 / 7.68
10	⅜"	17.15	1.65 / 13.85	2.31 / 12.53	3.20 / 10.75
15	½"	21.34	2.11 / 17.12	2.77 / 15.80	3.73 / 13.88
20	¾"	26.67	2.11 / 22.45	2.87 / 20.93	3.91 / 18.85
25	1"	33.40	2.77 / 27.86	3.38 / 26.64	4.55 / 24.30
32	1¼"	42.16	2.77 / 36.62	3.56 / 35.04	4.85 / 32.46
40	1½"	48.26	2.77 / 42.72	3.68 / 40.90	5.08 / 38.10
50	2"	60.33	2.77 / 54.79	3.91 / 52.51	5.54 / 49.25
65	2½"	73.03	3.05 / 66.93	5.16 / 62.71	7.01 / 59.01
80	3"	88.90	3.05 / 82.80	5.49 / 77.92	7.62 / 73.66
100	4"	114.30	3.05 / 108.20	6.02 / 102.26	8.56 / 97.18
125	5"	141.30	3.40 / 134.50	6.55 / 128.20	9.53 / 122.24
150	6"	168.28	3.40 / 161.48	7.11 / 154.06	10.97 / 146.34
200	8"	219.08	3.76 / 211.56	8.18 / 202.72	12.70 / 193.68
250	10"	273.05	4.19 / 264.67	9.27 / 254.51	12.70 / 247.65
300	12"	323.85	4.57 / 314.71	9.53 / 304.79	12.70 / 298.45

电热元件材料

材料	成分	最高温度（°C）	20°C 电阻率 Ω·mm²/m	电阻温度系数	备注
Kanthal A1 (FeCrAl)	Fe-Cr22-Al5.8	1400	1.45	~1.04 (20°C to max)	Most common furnace element. Good oxidation resistance. Brittle when hot – do not disturb.
Kanthal APM	Fe-Cr22-Al5.8 (PM)	1425	1.45	~1.04	Powder metallurgy version. Better creep resistance. Tube/strip elements.
Nikrothal 80 (NiCr)	Ni-Cr20	1200	1.09	~1.05	Nichrome 80/20. Good in reducing atmospheres. More ductile than FeCrAl.
Nikrothal 60	Ni-Cr15-Fe	1100	1.11	~1.06	Lower cost NiCr alloy. Up to 1100°C. Better for lower-temp furnaces.
SiC (Silicon Carbide)	SiC (self-bonded)	1625	~100-1000*	Negative to ~800°C, then positive	Rod/tube elements (Globar, Crusilite). Resistance DECREASES with temp initially. Requires tap transformer.
MoSi2 (Moly-D)	MoSi2	1850	~0.3 (cold), ~3.0 (hot)	~10:1 cold-to-hot ratio	U-shape or W-shape (Kanthal Super). Very high inrush current when cold. Must soft-start. Fragile cold, strong hot.
Molybdenum (Mo)	Mo (>99.95%)	1700 (vacuum/H2)	0.054	~4.5:1 cold-to-hot ratio	Vacuum/hydrogen furnaces only. Oxidises above 400°C in air. Rod, strip, or mesh.
Tungsten (W)	W (>99.95%)	2500 (vacuum)	0.055	~6:1 cold-to-hot ratio	Highest-temp metallic element. Vacuum only. Very brittle when cold. Mesh or rod.
Graphite	C (high purity)	2200 (vacuum/inert)	~8-14	Negative (resistance decreases with temp)	Vacuum furnaces, sintering. Rod, tube, or cloth. Burns in air >400°C.

电热元件表面负荷

元件型式	最高温度下最大表面负荷	典型设计负荷	备注
Kanthal A1 wire (coil)	3.5 W/cm²	1.5-2.5 W/cm²	Derate by 20% for vertical mounting, 30% for enclosed elements.
Kanthal A1 strip	4.0 W/cm²	2.0-3.0 W/cm²	Better radiation from flat surface vs wire coil.
NiCr 80/20 wire	2.5 W/cm²	1.2-2.0 W/cm²	Lower max load than FeCrAl due to lower max temp.
SiC rod (Globar)	15-20 W/cm²	5-10 W/cm²	Hot zone only (central section). Cold ends are low resistance.
MoSi2 (Super 33)	20-30 W/cm²	8-15 W/cm²	Very high loading capability. Must protect from drips/contact.

电缆截面与载流量（BS 7671）

铜芯 PVC 绝缘 70°C，依据 BS 7671。

截面 mm²	AWG 近似	单相（A）暗装	三相（A）暗装	电压降 mV/A/m	炉上典型应用
1.5	16	15.5	13.5	29	Control circuits, thermocouples
2.5	14	21	18	18	Instrument power, small actuators
4.0	12	27	24	11	Small heating circuits
6.0	10	34	31	7.3	Fan motors, small elements
10	8	46	42	4.4	Element sub-circuits
16	6	61	56	2.8	Element zone supplies
25	4	80	73	1.75	Main furnace feeds
35	2	99	89	1.25	Large furnace mains
50	1/0	119	108	0.93	Main switchboard feeds
70	2/0	151	136	0.63	Large installations
95	3/0	182	164	0.46	High-current bus bars/tails
120	4/0	210	188	0.36	Transformer secondaries

SCR / 可控硅控制方式

控制方式	说明	典型用途	谐波
Zero-cross firing (on/off)	Switches full cycles on/off. Time-proportioned.	Resistive heating elements. Most common for furnaces.	Minimal harmonics. Preferred by supply companies.
Phase-angle firing	Fires partway through each half-cycle.	SiC elements, transformers, lamp heaters, fast response.	High harmonics. May need harmonic filter. Check G5/4 compliance.
Single-phase	2 SCRs (back-to-back) or 1 SCR + diode.	Small zones <40A.	Causes neutral current. Max 3 per 3-phase supply (balanced).
Three-phase, 3-leg	6 SCRs (2 per phase).	Large zones, balanced load.	Star or delta element connection. Most efficient for >30kW.

IP 防护等级（IEC 60529）

IP 防护等级	固体防护	液体防护	典型用途
IP20	Fingers (>12.5mm)	None	Indoor control panels (standard)
IP40	Wires (>1mm)	None	Clean indoor environments
IP54	Dust protected	Splashing water	Workshop floor panels, outdoor sheltered
IP55	Dust protected	Water jets	Furnace-side panels, wash-down areas
IP65	Dust tight	Water jets	Harsh industrial, quench area, outdoor
IP66	Dust tight	Powerful water jets	Heavy wash-down, chemical exposure
IP67	Dust tight	Immersion (1m/30min)	Sensors, junction boxes in wet areas

单相电路公式

求解量	公式	示例
Power (kW)	kW = V × I × PF / 1000	240V × 50A × 1.0 = 12.0 kW
Current (A)	I = kW × 1000 / (V × PF)	10 kW / (240V × 1.0) = 41.7 A
kVA	kVA = V × I / 1000	240V × 50A = 12.0 kVA
Power Factor	PF = kW / kVA	10 kW / 12 kVA = 0.83

三相电路公式

求解量	公式	示例（415V）
Power (kW)	kW = √3 × V_line × I_line × PF / 1000	√3 × 415 × 100 × 0.95 = 68.3 kW
Line Current (A)	I = kW × 1000 / (√3 × V × PF)	50 kW / (√3 × 415 × 0.95) = 73.1 A
kVA	kVA = √3 × V_line × I_line / 1000	√3 × 415 × 100 = 71.9 kVA
Phase voltage (Star)	V_phase = V_line / √3	415 / √3 = 240 V
Phase current (Delta)	I_phase = I_line / √3	100 / √3 = 57.7 A

常用估算关系

换算	公式	备注
kW to Amps (3-ph, 415V)	A ≈ kW × 1.40 (at PF=1)	Quick estimate: 1 kW ≈ 1.4 A at 415V 3-phase
kW to BTU/hr	BTU/hr = kW × 3,412	For furnace rating conversions
HP to kW	kW = HP × 0.746	Motor ratings (fan motors, pump motors)
kW to kcal/hr	kcal/hr = kW × 860	For cooling system sizing
Resistance heating	P = V² / R = I² × R	For element power calculations
Cable sizing (approx)	1.5mm² to 10A, 2.5mm² to 20A, 4mm² to 32A	Rule of thumb for short runs — always check BS 7671

压力单位换算矩阵

从 \ 到	bar	psi	kPa	mbar	mmHg（Torr）	atm	inH₂O
1 bar	1	14.504	100	1000	750.06	0.9869	401.5
1 psi	0.06895	1	6.895	68.95	51.715	0.06805	27.68
1 kPa	0.01	0.1450	1	10	7.501	0.00987	4.015
1 mbar	0.001	0.01450	0.1	1	0.7501	9.87×10-4	0.4015
1 atm	1.01325	14.696	101.325	1013.25	760	1	406.8

流量单位换算矩阵

从 \ 到	m³/h	L/min	CFM	SCFH	US gal/min
1 m³/hr	1	16.667	0.5886	35.31	4.403
1 l/min	0.06	1	0.03531	2.119	0.2642
1 cfm	1.699	28.32	1	60	7.481
1 scfh	0.02832	0.4719	0.01667	1	0.1247

长度分数 / 小数 / mm 对照

分数	小数（in）	mm	分数	小数（in）	mm
1/64"	0.0156	0.397	17/32"	0.5313	13.494
1/32"	0.0313	0.794	9/16"	0.5625	14.288
1/16"	0.0625	1.588	5/8"	0.6250	15.875
3/32"	0.0938	2.381	11/16"	0.6875	17.463
1/8"	0.1250	3.175	3/4"	0.7500	19.050
5/32"	0.1563	3.969	13/16"	0.8125	20.638
3/16"	0.1875	4.763	7/8"	0.8750	22.225
7/32"	0.2188	5.556	15/16"	0.9375	23.813
1/4"	0.2500	6.350	1"	1.0000	25.400
5/16"	0.3125	7.938	1-1/4"	1.2500	31.750
3/8"	0.3750	9.525	1-1/2"	1.5000	38.100
7/16"	0.4375	11.113	2"	2.0000	50.800
1/2"	0.5000	12.700	3"	3.0000	76.200

AWG / SWG / 公制线径对照

电热元件线、热电偶线与导体的线规对照。

AWG	直径 mm	截面积 mm²	SWG	直径 mm	截面积 mm²
4/0 (0000)	11.68	107.2	7/0	12.70	126.7
3/0 (000)	10.40	85.0	6/0	11.79	109.1
2/0 (00)	9.27	67.4	5/0	10.97	94.5
1/0 (0)	8.25	53.5	4/0	10.16	81.1
1	7.35	42.4	1	7.62	45.6
2	6.54	33.6	2	7.01	38.6
4	5.19	21.2	4	5.89	27.3
6	4.11	13.3	6	4.88	18.7
8	3.26	8.37	8	4.06	13.0
10	2.59	5.26	10	3.25	8.30
12	2.05	3.31	12	2.64	5.48
14	1.63	2.08	14	2.03	3.24
16	1.29	1.31	16	1.63	2.08
18	1.02	0.823	18	1.22	1.17
20	0.812	0.518	20	0.914	0.657
22	0.644	0.326	22	0.711	0.397
24	0.511	0.205	24	0.559	0.245
26	0.405	0.129	26	0.457	0.164
28	0.321	0.0810	28	0.376	0.111
30	0.255	0.0509	30	0.315	0.0779
32	0.202	0.0324	32	0.274	0.0589
34	0.160	0.0201	34	0.234	0.0430
36	0.127	0.0127	36	0.193	0.0293
38	0.101	0.00797	38	0.152	0.0182
40	0.0799	0.00501	40	0.122	0.0117

标准状态定义（Nm³ / Sm³）

标准	符号	温度	压力	使用地区
Normal conditions	Nm³	0°C (273.15 K)	1.01325 bar (1 atm)	Europe (ISO 2533), gas industry standard
Standard conditions (US)	SCF, SCFH	60°F (15.56°C)	14.696 psia (1 atm)	USA, UK gas industry (sometimes)
Standard conditions (metric)	Sm³	15°C (288.15 K)	1.01325 bar (1 atm)	ISO 13443, European gas billing
Actual conditions	Am³, m³	Actual temperature	Actual pressure	What the flowmeter reads

气体体积换算系数

从	到	乘以
Nm³ (0°C, 1 atm)	Sm³ (15°C, 1 atm)	1.0549
Sm³ (15°C, 1 atm)	Nm³ (0°C, 1 atm)	0.9480
Nm³	SCF (60°F, 1 atm)	37.32
SCF	Nm³	0.02680
Sm³	SCF	35.39
SCF	Sm³	0.02826
Nm³/hr	SCFH	37.32
Litres (liquid N₂)	Nm³ gas	0.682
Litres (liquid Ar)	Nm³ gas	0.784
Litres (liquid O₂)	Nm³ gas	0.800
kg (N₂ gas)	Nm³	0.799
kg (Ar gas)	Nm³	0.561
kg (H₂ gas)	Nm³	11.12

炉工程物理常数

常数	符号	数值	用途
Stefan-Boltzmann constant	σ	5.67 × 10-8 W/m²·K4	Radiation heat transfer: q = σεA(T14 – T24)
Universal gas constant	R	8.314 J/(mol·K)	Ideal gas law: PV = nRT
Boltzmann constant	kB	1.381 × 10-23 J/K	Statistical thermodynamics, gas kinetics
Standard atmosphere	atm	101,325 Pa = 1013.25 mbar	Pressure reference
Specific heat of air	Cp	1.005 kJ/(kg·K) at 20°C	Air heating calculations
Density of air	ρ	1.225 kg/m³ at 15°C, 1 atm	Flow calculations
Density of water	ρ	1000 kg/m³ at 4°C	Quench tank sizing
Specific heat of water	Cp	4.186 kJ/(kg·K)	Quench heat extraction calculations
Specific heat of steel	Cp	~0.50 kJ/(kg·K) at 20°C	Heat-up energy estimation: Q = mCpΔT
Latent heat of steam	Lv	2,257 kJ/kg at 100°C	Steam generation, quench boiling calculations
Gravitational acceleration	g	9.81 m/s²	Flue gas buoyancy, chimney draft