Stainless steel grade 430 is a non-hardenable steel containing straight chromium, and belongs to the ferritic group of steels. This steel is known for its good corrosion resistance and formability, coupled with practical mechanical properties. It can be used in certain chemical applications due to its resistance to nitric acid.

Grade 430F stainless steel is usually provided in bar form to be used in automatic screw machines.

Grade 434 has similar properties as grade 430, although it is a molybdenum-bearing version. The molybdenum content enhances its corrosion resistance.

Typical applications for 430 grade include:

• Linings for dish washers
• Refrigerator cabinet panels
• Automotive trim
• Lashing Wire
• Element Supports
• Stove trim rings
• Fasteners
• Chimney Liners

Heat Treatment

• Solution Annealing – Heat to 815-845°C, hold for ½ hour per 25mm of thickness, slow furnace cool to 600°C and then quickly air cool. Slow cooling from 540-400°C will cause embrittlement.
• Sub-Critical anneal – Heat to 760-815°C and then air cool or water quench.
• This grade is not hardenable by thermal treatment.

Welding

• Pre-heat at 150-200°C if welding is necessary.
• Embrittlement in the weld metal and heat affected zone can be relieved by a post-weld anneal at 790-815°C
• Grain refinement will not occur.

Machining

• Easier to machine than the standard austenitic grades such as 304.
• Still a tendency for galling and pick-up on the cutting tool.
• Bars that have been lightly drawn are easier to machine than those in the annealed condition.
• Grade 430F, the free machining version of 430, is very much easier to machine.

Fabrication

• Lower work hardening rate makes bending and forming somewhat easier than for grade 304
• Lower ductility restricts very severe operations.
• Severe bends should be made with the bend axis at right angles to the rolling direction.
• Severe cold heading of 430 wire is possible.