Type 430 are low carbon ferritic stainless steels which, in mildly corrosive environments or atmospheric exposures, have corrosion resistance approaching that of some nickel stainless steels. These alloys are oxidation resistant at elevated temperatures. Types 430 and 434 are ductile, do not work harden readily, and can be formed using a variety of roll forming or mild stretch bending operations as well as the more common drawing and bending processes.
Types 430 should be machined at speeds about 60% of those used for a similar operation on reference type B1112. Your Allegheny Ludlum representative will furnish information on free-machining modifications of these alloys.
Allegheny Types 430 can be welded by all commercial processes normally used to weld stainless steels. For best results the stainless steel parts to bejoined must be completely free of grease, oil or other surface contamination. Satisfactory joints can be made with austenitic weld deposits of base metal. If the welded structure is to be subjected to thermal cycling, filler wire of the base metal composition should be used to avoid differences in thermal expansion which can cause bucking.
Welding these alloys will cause a decrease in ductility of the weld and heat affected zones due to the formation of martensite during cooling. The weld heat affected zone will also suffer a marked loss of corrosion resistance in some environments, Both ductility and corrosion resistance can be restored by annealing.
Both welding and subsequent annealing will form a scale or heat tint of these alloys. These discolorations must be completely removed to realize maximum corrosion resistance.