What is 4340 annealed?

4340 Hot Rolled Annealed Aircraft Quality Alro Stocks AISI 4340 HR AQ – a highly alloyed steel with high nickel and chromium content which assures deep hardening when oil quenched, with high strength characteristics throughout the section. Used for heavily stressed parts operating under strenuous conditions.

How do you anneal 4340 steel?

Annealing. To obtain a pearlitic structure on certain parts for machining, 4340 should be annealed at a nominal temperature of 1525 º F (830 º C,) cooling to 1350 º F (730 º C) and furnace cooling to 1130 º F (610 º C) at a rate of 20 º F (11 º C) per hour, then air cooling.

What does AISI 4340 mean?

AISI 4340 is a heat treatable, low alloy steel containing nickel, chromium and molybdenum. It is known for its toughness and capability of developing high strength in the heat treated condition while retaining good fatigue strength.

How strong is 4340 steel?

4340 is a 1.8% nickel – chromium – molybdenum high hardenability high tensile steel – generally supplied hardened and tempered in the tensile range of 930 – 1080 Mpa (condition U) – (Rc 28 – 36).. Characterised by high strength and toughness in relatively large sections.

Is 4340 forged steel?

4340 forged steel is a heat-treatable, low iron-carbon alloy steel to which alloying elements have been added. It contains nickel, chromium and molybdenum. Machining is best done with the alloy steel 4340 in the annealed or normalized and tempered condition.

How hard can you get 4340 steel?

Surface hardness achievable is 600 to 650HV. Atlas 4340 can be surface hardened to 58HRC (water quench) or surface hardened to between 53 to 55HRC (oil quench). Tempering at 200°C.

Is 4340 a tool steel?

4340 steel is an “ultra-high” strength steel classified a medium-carbon, low-alloy steel. 4340 has high strength, ductility, toughness, creep resistance, and fatigue resistance relative to most other steels.

Which is better forged or billet crankshaft?

With a forged crank, the forging process creates an interwoven grain structure. With a billet crank, the grain structure just runs parallel with the crank. Billet is a better option if you need a custom one-off crank since it doesn’t require expensive tooling equipment.

What is AISI 4340 steel called?

AISI 4340 Alloy Steel (UNS G43400)

Is billet stronger than steel?

Billet does tend to be stronger but it’s not necessarily true that a part made from billet aluminum is always stronger. That leads us to the main reason why billet material tends to be stronger. That is, alloys that are better for machining tend to be stronger while alloys that are better for casting tend to be softer.

Is billet better than cast?

Billet aluminum is generally considered a stronger material than cast. Billet parts are made from a single block of material that is machined down on a CNC mill. The result is a gorgeous part that can be made to match an engineer’s design with perfect precision.

What do you need to know about 4340 alloy steel?

Since 4340 alloy steel is air hardened, the welded parts should be either annealed or normalized and tempered shortly after welding. The high hardness of 4340 alloy steel requires that the material be welded in the annealed or tempered state and then heat treated to resist martensite formation and cold cracking.

What are the mechanical properties of AISI 4340?

The mechanical properties of annealed AISI 4340 alloy steel are displayed in the following table. Properties. Metric. Imperial. Tensile strength. 745 MPa. 108000 psi. Yield strength. 470 MPa.

Which is the best welding method for AISI 4340?

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. AISI 4340 alloy steel is heat treated at 830°C (1525°F) followed by quenching in oil. AISI 4340 alloy steel is forged at 427 to 1233°C (1800 to 2250°F).

Why is oil quenching used for AISI steel 4340?

Oil quenching is normally used for 4340 as the alloy’s hardenability is suited to this quenching method. Tempering is carried out to relieve stresses from the hardening process, but primarily to obtain mechanical properties required for the final application.