Looking forward to working with us

Home page

AISI 4340 Steel 36CrNiMo4 1.6511 EN24 817M40 SNCM439

AISI 4340 Steel 36CrNiMo4 1.6511 EN24 817M40 SNCM439

AISI 4340 (E4340) alloy steel is a medium carbon, low alloy steel known for its toughness and strength. Machining is done typically in the annealed condition. 4340 steel properties offer good ductility in the annealed condition, allowing it to be bent or formed. Fusion and resistance welding is also possible with our 4340 steel from stock.

keywords:

Product Categories

Alloy Steel Plate

Email：

WhatsApp：

Product introduction

AISI 4340 steel is a medium carbon, low alloy steel known for its toughness and strength in relatively large sections. AISI 4340 is also one kind of nickel chromium molybdenum steels. 4340 alloy steel is generally supplied hardened and tempered in the tensile range of 930 – 1080 Mpa. Pre hardened and tempered 4340 steels can be further surface hardened by flame or induction hardening and by nitriding. The 4340 steel has good shock and impact resistance as well as wear and abrasion resistance in the hardened condition. AISI 4340 steel properties offer good ductility in the annealed condition, allowing it to be bent or formed. Fusion and resistance welding is also possible with our 4340 alloy steel. ASTM 4340 material is often utilized where other alloy steels do not have the hardenability to give the strength required. For highly stressed parts it is excellent choice. AISI 4340 alloy steel can also be machined by all customary methods.

Due to availability the ASTM 4340 grade steel is often substituted with European based standards 817M40/EN24 and 1.6511/36CrNiMo4 or Japan based SNCM439 steel. You have the detailed data of 4340 steel below.

1. AISI Alloy 4340 Steel Supply Range

4340 Steel Round Bar: diameter 8mm – 3000mm (*Dia30-240mm in stock in annealed condition, immediate shipment)

4340 Steel Plate: thickness 10mm – 1500mm x width 200mm – 3000mm

4340 Steel Grade Square: 20mm – 500mm

Surface Finish: Black, Rough Machined, Turned or as per given requirements.

2. AISI 4340 Steel Specification and Relevant Standards

Country	USA	Britain	Britain	Japan
Standard	ASTM A29	EN 10250	BS 970	JIS G4103
Grades	4340	36CrNiMo4/ 1.6511	EN24/817M40	SNCM 439/SNCM8

3. ASTM 4340 Steels And Equilvalents Chemical Composition

Standard	Grade	C	Mn	P	S	Si	Ni	Cr	Mo
ASTM A29	4340	0.38-0.43	0.60-0.80	0.035	0.040	0.15-0.35	1.65-2.00	0.70-0.90	0.20-0.30
EN 10250	36CrNiMo4/ 1.6511	0.32-0.40	0.50-0.80	0.035	0.035	≦0.40	0.90-1.20	0.90-1.2	0.15-0.30
BS 970	EN24/817M40	0.36-0.44	0.45-0.70	0.035	0.040	0.1-0.40	1.3-1.7	1.00-1.40	0.20-0.35
JIS G4103	SNCM 439/SNCM8	0.36-0.43	0.60-0.90	0.030	0.030	0.15-0.35	1.60-2.00	0.60-1.00	0.15-0.30

4. AISI Alloy 4340 Steel Mechanical Properties

Mechannical Properties (Heat Treated Condition )	Condition	Ruling section mm	Tensile Strength MPa	Yield Strength MPa	Elong. %	Izod Impact J	Brinell Hardness
	T	250	850-1000	635	13	40	248-302
	T	150	850-1000	665	13	54	248-302
	U	100	930-1080	740	12	47	269-331

	V	63	1000-1150	835	12	47	293-352
	W	30	1080-1230	925	11	41	311-375
	X	30	1150-1300	1005	10	34	341-401

	Y	30	1230-1380	1080	10	24	363-429
	Z	30	1555-	1125	5	10	444-

Thermal Properties

Properties	Metric	Imperial
Thermal expansion co-efficient (20°C/68°F, specimen oil hardened, 600°C (1110°F) temper	12.3 µm/m°C	6.83 µin/in°F
Thermal conductivity (typical steel)	44.5 W/mK	309 BTU in/hr.ft².°F

5. Forging of 4340 Alloy Steel

Preheat the steel 4340 first, heat up to 1150°C – 1200°C maximum for forging, hold until temperature is uniform throughout the section.

Do not forge below 850 °C. 4340 has good forging characteristics but care must be taken when cooling as the steel shows susceptibility to cracking. Following forging operation the work piece should be cooled as slowly as possible. And cooling in in sand or dry lime is recommended etc.

6. AISI 4340 Steel Grade Heat Treatment

Stress Relieving
For pre-hardened steel stress relieving is achieved by heating steel 4340 to between 500 to 550°C. Heat to 600 °C – 650 °C, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air.

Annealing
A full anneal may be done at 844°C (1550 F) followed by controlled (furnace) cooling at a rate not faster than 10°C (50 F) per hour down to 315°C (600 F). From 315°C 600 F it may be air cooled.

Tempering
AISI 4340 alloy steel should be in the heat treated or normalized and heat treated condition before tempering. The tempering temperature for depends upon the strength level desired. For strength levels in the 260 – 280 ksi range temper at 232°C (450 F). For strength in the 125 – 200 ksi range temper at 510°C (950 F). And don’t temper the 4340 steels if it is in the 220 – 260 ksi strength range as tempering can result in degradation of impact resistance for this level of strength.

Tempering should be avoided if possible within the range 250 °C – 450 °C due to temper brittleness.

Flame or Induction Hardening
As mentioned above, pre-hardened and tempered 4340 steel bars or plates can be further surface hardened by either the flame or induction hardening methods resulting in a case hardness in excess of Rc 50. AISI 4340 steel parts should be heated as quickly as possible to the austenitic temperature range (830 °C – 860 °C) and required case depth followed by an immediate oil or water quenching, depending upon hardness required, workpiece size/shape and quenching arrangements.

Following quenching to hand warm, tempering at 150°C – 200°C will reduce stresses in the case with minimal effect on its hardness.

All de-carburised surface material must first be removed to ensure best results.

Nitriding
Hardened and tempered 4340 alloy steel can also be nitrided, giving a surface hardness of up to Rc 60. Heat to 500°C – 530°C and hold for sufficient time (from 10 to 60 hours) to develop the depth of case. Nitriding should be followed by slow cooling (no quench) reducing the problem of distortion. The nitrided grade 4340 materials can therefore be machined to near final size, leaving a small grinding allowance only. The tensile strength of the 4340 steel material core is usually not affected since the nitriding temperature range is generally below the original tempering temperature employed.

Surface hardness achievable is 600 to 650HV.

7. Machinability

Machining is best done with the alloy steel 4340 in the annealed or normalized and tempered condition. It can be readily machined by all conventional methods such as sawing, turning, drilling etc. However in the high strength conditions of 200 ksi or greater the machinability is only from 25% to 10% that of the alloy in the annealed condition.

8. Welding

Welding of steel 4340 in the hardened and tempered condition (as normally supplied), is not recommended and should be avoided if at all possible, because of the danger of quench cracking, as the mechanical properties will be altered within the weld heat affected zone.

If welding must be carried out, pre-heat to 200 to 300°C and maintain this while welding. Immediately after welding stress relieve at 550 to 650°C, prior to hardening and tempering.

If welding in the hardened and tempered condition is really necessary, then the work piece, immediately on cooling to hand warm, should be if possible stress relieved at 15 °C below the original tempering temperature.

Warehouse Storage

TIANYI Steel (Shandong) Co., Ltd. is located in the beautiful Shandong Province. With the continuous development of business, the company's business scope continues to expand. The company has a group of professional sales staff to provide customers with high-quality services. The company is committed to providing customers with high-quality, low-cost steel products. We have won the trust and praise of our customers with our commitment and quality-oriented service concept.

Packing and shipping

Our main products include: carbon steel plate, carbon steel pipe, color-coated sheet/coil, galvanized sheet/sheet tube/coil/corrugated sheet/plate steel (I-beam channel steel H-beam), long product, galvanized pipe, Welded pipe, gas pipe, spiral pipe, plate, thread, wire, automobile flat steel, etc. The stock of each specification is sufficient. And it is an excellent distributor of Chinese state-owned enterprises: Baosteel, Baotou Steel, Anshan Iron and Steel, Baotou Iron and Steel, and other national iron and steel enterprises.

Application field

Our advantage is to integrate market information, quickly find the products you need, provide high-quality price concessions, one-stop service, and provide you with products accurately and quickly. We always adhere to the tenet of "quality first, customer first, high-quality service, honesty and trustworthiness". With high-quality products, good reputation and high-quality service. We are committed to win-win cooperation with domestic and foreign merchants. We look forward to common development and create brilliance together. Feel free to contact our team to experience supreme service and quality products. Looking forward to working with us.

Customer praise

Customer visit

FAQ

Q1:Can you send samples?

A:Of course, we can provide customers with free samples and express shipping service to all over of the world.

Q2:What product information do I need to provide?

A:Please kindly provide the grade, width, thickness, surface treatment requirement should you have and quantities you need to purchase.

Q3:It's my first time to import steel products, can you help me with it?

A:Sure,we have agent to arrange the shipment, we will do it together with you.

Q4:What about product prices information?

A:Prices various according to periodic price changes of raw materials.

Q5:What ports of shipment are there?

A:Under normal circumstances, we ship from Shanghai, Tianjin, Qingdao, Ningbo ports, you can specify other ports according to your needs.

Q6:What is your terms of payment ?

A:Payment<=1000USD, 100% in advance. Payment>=1000USD, 30% T/T in advance ,balance before shipment or based on BL copy or LC at sight.

Q7.Do you provide custom made Products service?

A: Yes,if you have your own design , we can produce according to your specification and drawing.

Q8:What are the certifications for your products?

A:We have ISO 9001, MTC, third parties’ inspections are all available such SGS, BV ect.

Q9:How long does your delivery time take?

A:In general, our delivery time is within 7-15 days, and may be longer if the quantity is extremely large or special circumstances occur.

Q10: How many countries you already exported to?

A:We have exported to America, Canada, Brazil, Chile, Colombia, Russia, Ukraine, Thailand, Myanmar, Vietnam, India, Kenya, Ghana,somalia and other African countries.Our export experience is rich, we familiar with different market demands, can help customers avoid a lot of trouble.

Alloy Steel Plate