- EN / Grade
- 4340 Air Melt
- Other designations / UNS
- SAE 4340 · Air Melt
UNS G43400 - Family
- Alloy steel
Machining hardness and service hardness
Choosing an initial condition suitable for machining does not mean abandoning final strength. Annealed or normalized-and-tempered stock may be machined before final processing. Section size, quench response and final tempering condition determine the properties; the same result should not be expected in every thickness.
Similar chemistry, different acceptance requirements
Air Melt and VAR are not alternative spellings of the same procurement requirement. AMS 6415 is one example for the bar and forging family, while AMS 6484 explicitly describes normalized-and-tempered delivery. Listing these specifications alone does not establish vacuum remelting.
Defining an order for a machine component
Finished dimensions, machining allowance, delivery hardness and any impact-test requirement form the basis of the enquiry. State welding or plating plans at the outset. For high-strength 4340 components, post-weld condition and corrosion protection cannot be decided from the grade name alone.
Typical application areas
Transmission shafts, high-strength connections, mechanical component blanks.
Product and cutting options
Share the section and dimensions you require for this grade. Availability is assessed for each request; the catalogue does not represent live stock.
What to specify in your enquiry
- Grade designation and applicable material standard
- Section, finished dimensions and machining allowance
- Quantity, delivery condition and certificate requirements
Frequently asked questions
Can I request 4340 Air Melt in cut lengths?+
Share your required section, dimensions and quantity. Our team will assess suitable supply and cutting options for the specific grade.
Are the listed grade designations interchangeable?+
Designation systems can overlap, but they do not make every specification identical. Use the exact standard and certificate requirements defined by your project.