The main components of 304 stainless steel and 304L stainless steel are 18% chromium (Cr) and 8% nickel (Ni); their main difference is that 304L stainless steel is a low carbon 304 steel. Under normal conditions, 304L stainless steel has corrosion resistance. Similar to 304 stainless steel, but after welding or after stress relief, 304L stainless steel has excellent resistance to grain boundary corrosion.
In terms of price, 304L stainless steel is higher than 304 stainless steel. 304L stainless steel is a low-carbon stainless steel, which is mainly suitable for welding processes. When welding, the use of 304L stainless steel can effectively reduce welding corrosion.
According to the hardness standard, 304 stainless steel is better than 304L stainless steel, because the level of carbon content directly affects the hardness of stainless steel. In addition, there are 304H stainless steel series, H means high carbon content.
About the substitution of materials
In daily production applications, material substitution is often involved. In people's minds, it is only natural that materials "replacing low with high and thin with thick", in fact, this view is wrong. The material substitution needs to be divided according to the situation. Take 304 stainless steel, 304L stainless steel, and 304H stainless steel to illustrate. Generally speaking, 304L stainless steel products have lower carbon content and better corrosion resistance than 304 stainless steel products, so 304L stainless steel products can be used instead of 304 stainless steel materials. In fact, the strength of 304 stainless steel is higher than that of 304L stainless steel. When it is designed according to 304 stainless steel, if it is replaced by 304L stainless steel, it will cause insufficient strength. Also, when the service temperature of austenitic stainless steel is higher than 525 °C, the carbon content in the steel should not be less than 0.04%. 304L stainless steel cannot be used at this time. Therefore, it is wrong to think that 304L stainless steel products can be used instead of 304 stainless steel products. Whether it can be used is related to the occasion of use, and according to the regulations, we do not have the right to "substitute materials", only the original design department can have the right to Carry out the work of "material substitution", please remember this point!