AISI 4340 EN24 817M40 Hot Rolled Alloy Steel Round Bar

AISI 4340 EN24 817M40 Hot Rolled Alloy Steel Round Bar

1: AISI 4340 Steel 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.

4340 Steel Stock in Warehouse

2: AISI 4340 Quality Standard

AISI 4340 steel according to ASTM A29-05.

3: AISI 4340 Steel Equivalent

4: AISI 4340 Steel Chemical Composition

5: AISI 4340 Steel Mechanical Properties 

The mechanical properties mainly include tensile strength, yield strength, elongation, area or reduction, hardness, impact value, non-metalic inclusion etc. Different heat treatment, the mechanical properties will be different, such as normalized, tempered, QT. If you want to know the properties, kindly contact the salesman.

6: Qilu Company Profile

Hunan Qilu was engaged in steel exporting since 2008 year, the former was the sales company for Qilu Special Steel co.,ltd which was founded in 1986 year. Now Hunan Qilu Metal is one of most professional steel manufacturer and exporter in China. We already exported steel material to Germany, UK, Ireland, Greece, Italy, Poland,Belgium, Estonia, Latvia, Spain, France, Netherlands, Portugal, Czech republic, Finland, Russia, Belarus, Canada, Mexico, Brazil, Chile, Colombia, Peru, Argentina, Venezuela, Thailand, Indonesia, Vietnam, Singapore, Malaysia, Philippines, UAE, South Africa, Zambia, Australia etc.

7: Production Equipment

The company owns advanced special steel smelting facilities and forging processing equipment, the main steel-making equipment include 2 set of 50t and 25t ultra-high power electric arc furnaces, 2 set of 60t and 30t LF refining furnaces, 2 set of 60t and 30t vacuum degassing refining furnace. 4 sets of 1-20t electroslag re-melting furnaces.

The main forging equipment mainly include:3 sets of 3t 5t and 8t electro-hydraulic hammers, 3 sets of high-speed forging units of 1600t, 2000t and 4500t respectively.

8: Our Company Certificate

We already passed ISO 9000 : 2015 certificate of quality system, and we could supply steel forging material with all kinds of Classification Society Certification, such as ABS, ,DNV, BV, CCS etc. We also supplied steel material to oil industry with API certificate, such as API20B, API6A etc.

9: Stock&Warehouse

Besides forging material, we also supply hot rolled material from Dongbei special steel, Tiangong, Changcheng special steel, Lihuai Special Steel, Laisteel, Juneng steel, Yongsteel, Xinxin steel, Shijiazhuang steel etc. We have two warehouses for hot rolled material. Further processing such as heating treatment, rough machining and milled are also provided by us.

10: AISI 4340 Steel Overviews

11: AISI 4340 Steel Tolerance

12: Packing& Delivery

For the delivery, we will choose LCL, FCL and Bulk carrier according to order quantity. Usually if the quantity is less than 10tons, we will recommend LCL. If the quantity is more than 100tons, we will recommend bulk carrier. Usually FCL will be the most common for delivery.

In order to better ensure the safety of your goods, we will provide professional, environmentally friendly, convenient and efficient packaging services. Such as pallet, wooden box, package with woven bag etc.

13: AISI 4340 Steel Heat Treatment

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.

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.

14: AISI 4340 Steel Application

4340 alloy steels are used for aircraft landing gear, automotive, oil and gas drilling, warm and cold forming, machine building, transfer systems like power transmission gears and shafts, general engineering industries and structural use applicatios such as heavy duty shafts, gears, axles, spindles, couplings, pins, chucks, molds and so on.

15: Delivery Condition

For hot forged or hot rolled bar, usually the delivery condition is hot forged or rolled, annealed or QT, black surface or rough turned.
For hot forged plate, usually the delivery condition is hot forged, annealed or QT, milled surface.
For hot rolled plate, usually the delivery condition is hot rolled, annealed or QT, black surface.