4340 Steel

Features of 4340 Steel

• 1 AISI 4340 steel is a high-quality quenched and tempered Alloy Structural Steel, It belongs to the high-quality medium carbon, oil quenched & tempered hardness is 28-34 HRC.
  AISI 4340 annealed with hardness is less than 250HB.
   
  AISI 4340 steel property is very similar with GB 40CrNiMo steel, JIS SNCM439 and DIN 1.6511 36CrNiMo4 Alloy structural steel. At most work environment, AISI 4340 is equivalent with 40CrNiMo, 1.6511 36CrNiMo4, SNCM439 steel.
   
  1.Form of Supply
   
  AISI 4340 Alloy structural steel, we can supply 4340 steel with round bar, steel flat bar, plate, block etc.
  2.Chemical composition
   
  Element ⇔ Content (%)
  ♦Iron, Fe ⇔95.195 – 96.33
  ◊Nickel, Ni ⇔ 1.65 – 2.00
  ♦Chromium, Cr ⇔0.700 – 0.900
  ◊Manganese, Mn ⇔0.600 – 0.800
  ♦Carbon, C ⇔ 0.370 – 0.430
  ◊Molybdenum, Mo ⇔ 0.200 – 0.300
  ♦Silicon, Si ⇔ 0.150 – 0.300
  ◊Sulfur, S ⇔ 0.0400
  ♦Phosphorous, P ⇔ 0.0350
   
  3.Applications
   
  AISI 4340 steel is one alloy structural steel, 4340 is used for engineering structural, be used as require good toughness, high strength, as well as the important conditioning of large size, heavy machinery such as high load of axial, turbine shaft, larger than 250 mm in diameter of helicopter rotor shaft, turbojet engine turbine shaft, blade, high load of transmission parts, fasteners of the crankshaft. Gear, etc.; It also can be used for operating temperature over 400 ℃ of rotor shaft and blade, etc.; And after nitriding processing can also be used to make special performance requirements of the important parts, after low temperature tempering or can be used for ultra-high strength steel after isothermal quenching
   
  4. Machinability
  AISI 4340 alloy steel can be machined using all conventional techniques. Machining process can be performed in the annealed or normalized and tempered conditions.
   
  5.Forming
  AISI 4340 alloy steel has good ductility and formability in the annealed condition. It can be bent or formed by pressing or spinning in the annealed state.
   
  6.Welding
  AISI 4340 alloy steel can be welded using fusion or resistance welding methods. Preheat and post heat weld procedures are followed while welding this steel by established methods.
   
  7.Forging
  AISI 4340 alloy steel is forged at 427 to 1233°C (1800 to 2250°F).
   
  8.Cold Working
  AISI 4340 alloy steel can be cold worked using all conventional methods in the annealed condition. It has high ductility.
   
  9.Annealing
  AISI 4340 alloy steel is annealed at 844°C (1550°F) followed by cooling the furnace.
   
  10.Tempering
  AISI 4340 alloy steel should be in the heat treated or normalized and heat treated condition before tempering. Tempering temperatures depend upon the desired strength level.
   
  11.Hardening
  AISI 4340 alloy steel can be hardened by cold working or heat treatment.
  
  ALLOY STRUCTURE STEEL合金结构钢
  

  编号 NO:	近似钢号					用途	Application
  	中国GB	美国AISI	德国DIN	日本JIS	外企 Foreign Enterprise
  1	40Cr	5140	1.7035 41Cr4	SCR440		广泛使用的轴、螺栓、连杆等	For shaft,screw bolt, joint shaft in widely use
  2	30CrNi3	3435	1.5755 31NiCr14	SNC631		承受大冲击、扭力载的轴、螺栓、连杆等	For shaft,bolt, join td-olt endureing sudden impacting
  3	40CrNiMo	4340	1.6582 36CrNiMo4	SNCM439		大直径汽轮机叶片、轴和螺栓等	For vane,shaft bolt of large dia steamer
  4	35CrMo	4135	1.7220 34CrMo4	SCM435		汽轮机主轴400°C使用螺栓、轧机人字齿、锤杆等	For main shaft of steamer,bolt for 400°C,Hummar shank
  5	42CrMo	4140	1.7225 42CrMo4	SCM440		同35CrMo,便截面可更大，强度也高	Same as 35CrMo with big section supper force
  6	*35CrMoV	4135		SCM435		使用温度≤500°C汽轮机叶轮，压缩机转子等	For steamer vane againest 500°C rotor of compresser
  7	50CrV	6150	1.8159 51CrV4	SUP10		在200°C使用弹簧钢供内燃机，轿车等用	Spring steel for gas engine,car within 200°C
  8	60Si2MnA	9260	55Si7	SUP7		主要用于汽车、机车、拖拉机等专用弹簧	Spring steels for car, engine and tractor etc.
  9	60Si2CrA	9254	1.0961 60SiCr7	SUP12		在250°C内用作高载荷的大型弹簧	Spring steel for big gas engine, pump,crusher etc,with in 250°C
  10	55CrMnA	5155	1.7176 55Cr3	SUP9		用作重载荷，高应力条件下的大型弹簧，如汽车、机车等	Spring steel for car,engine,tractor etc.

   

  编号 NO:	合金结构钢化学成份(% ) Chemical composition										退火状态 硬度≤ Annealed Hardness	力学性能（≤）					热处理温度(℃) Heal Treatment Temp
  	C	Si	Mn	P≤	S≤	Cr	W	Mo	V			RM (MPa)	RM (MPa)	Ae %	Z %	A(S)	淬火  Quench	回火 Tempering
  1	0.40	0.30	0.70	0.025	0.025	1.00	≤0.25	—	—		207	980	785	9	45	47	850°C 油Oil	520°C 水/油
  2	0.30	0.30	0.50	0.025	0.025	0.80	3.00	—	—		241	980	785	9	45	63	850°C 油Oil	500°C 水/油
  3	0.40	0.30	0.55	0.025	0.025	0.80	1.35	0.20	—		269	980	835	12	55	78	850°C 油Oil	600°C 水/油
  4	0.33	0.30	0.60	0.025	0.025	1.00	≤0.25	0.20	—		229	980	835	12	45	63	850°C 油Oil	550°C 水/油
  5	0.42	0.30	0.60	0.025	0.025	1.00	≤0.25	0.20	—		229	1080	930	12	45	63	850°C 油Oil	560°C 水/油
  6	0.35	0.30	0.60	0.025	0.025	1.20	≤0.25	0.20	0.15		241	980	835	12	45	63	850°C 油Oil	550°C 水/油
  7	0.50	0.30	0.70	0.025	0.025	1.00	≤0.25	—	0.15		255	1280	1130	10	40		850°C 油Oil	500°C 水/油
  8	0.60	1.80	0.85	0.020	0.020	0.18	—	—	—		321	1570	1375	5	20		870°C 油Oil	440°C 水/油
  9	0.60	0.60	0.60	0.030	0.030	0.80	—	—	—		321	1765	1570	6	20		870°C 油Oil	420°C 水/油
  10	0.55	0.36	0.70	0.025	0.025	0.80	—	—	—		321	1225	1080	9	20		860°C 油Oil	510°C 水/油