astm a240 is a standard specification for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and for general applications
the astm a240 plate corresponds to a specification that caters to chromium and chromium alloy steel grades such as 304 or 316. while the grade of steel utilized for alloy strictly depends on the application, namely the kind of chemical exposure, and primary characteristics of the application i.e. - tensile strength and resistance to corrosion. suppose if the price is the key factor in the application, most suppliers prefer using grade 304 as the material grade for astm a240 foils. grade 304 offers moderate to good resistance to corrosion with good tensile properties. however, if the application is one that requires to withstand much stronger conditions, say like seawater, then grade 316 astm a240 clad sheet would be the preferred choice for marine engineering purposes. this being said, the weldability properties of both grade 304 and 316 are good. but the higher content of carbon in the alloy of stainless steel astm a-240 sheet prevents the alloys from reaching their whole potential with regards to their welding characteristics.
modified from the most versatile grades of stainless steel, the astm a240 304l plate is characteristically similar to grade 304, with one small exception. those stainless steel grades marked as l after the said grade is an indication of a low carbon alloy. low carbon alloys are designed to cater to one specific property, that is weldability. unlike the regular alloy grades, the astm a240 316l stainless steel plate does not accommodate the formation of grain boundary precipitates, particularly in the heat affected weld area. this, in turn, is what makes the alloy more resilient to corrosion that can occur after welding.
materials
a240 type | raw material |
304 | 18-8 chromium nickel austenitic stainless steel |
uns s31803 | ferritic / austenitic duplex stainless steel |
316l | low carbon, chromium nickel molybdenum austenitic stainless steel |
uns s32750 | ferritic / austenitic super duplex stainless steel |
321 | titanium stabalized 18-8 chromium nickel austenitic stainless steel |
410 | 12% straight chromium martensitic stainless steel |
uns s31254 | high moly austenitic stainless steel |
904l | high nickel molybdenum super austenitic stainless steel |