The Fundamentals of Stainless Steel Brazing

Posted by Hadley on March 23rd, 2018

Stainless steel is distinguished from carbon steel by its higher chromium content - a trait that provides the metal its lustrous look. Though chromium is resistant to corrosion below typical temperatures, it becomes unstable and oxidizes when it really is heated inside a furnace that consists of oxygen. Consequently, heat treating procedures for stainless steel are created to prevent chromium from oxidizing. The brazing course of action is no exception.

304l stainless steel sheet brazing is similar to carbon steel brazing in a few approaches. One example is, the same joint clearance among work pieces is maintained; each types of metal are cleaned prior to entering the furnace, and the pieces could possibly be fixed in the exact same fashion when placed inside the furnace. Even so, brazing chromium alloys and brazing carbon alloys are several procedures. Treating the former needs particular focus to certain items that treating the latter does not.

Joint Design and style

.0015" is definitely the encouraged clearance for brazing joints. Nevertheless, mainly because filler metal is freer flowing with stainless steel than other types of metal, unique care should be taken to make sure suitable joint design and style. To prove the point, a joint clearance that may be a thousandth of an inch also narrow or as well wide could generate a joint that fractures below a lower stress threshold than expected. For assemblies which are weight bearing, reaching right joint style may be an essential aspect of our product security.

Cleanliness

All metals advantage from getting cleaned ahead of entering the furnace, but chromium alloys is in particular sensitive for the presence of foreign substances which include dirt, grease, and rust. Whilst the integrity of some alloys is only mildly affected by such substances, chromium alloys are hugely affected by any type of coating. For this reason, chromium alloys should undergo a more rigorous cleaning process than most sorts of metal ahead of brazing commences.

Cooling

The cooling process for chromium alloys must be controlled to stop inter-granular corrosion that outcomes from carbide precipitations that type along grain boundaries. If corrosion occurs, the metal's corrosion resistance will diminish. In the event the corrosion is serious adequate, cracking could also result. Rapidly cooling the metal by way of the vital transformation variety aids avoid these occurrences. With non-chromium alloys, a rapid, controlled cooling cycle is often less integral to the high quality in the assembly.

Furnace Atmosphere

The most important difference amongst 306l stainless steel sheet brazing and carbon steel brazing entails furnace atmosphere. Some alloys will be treated inside the presence of oxygen with couple of ill effects, but chromium alloys react by forming oxides. Furthermore to creating the metal appear drossy, oxide scale lowers the strength of assembly joints. To prevent these occurrences, chromium alloys are treated within a continuous furnace or maybe a vacuum furnace that maintains an oxygen-free atmosphere

Conclusion

Stainless steel brazing differs from carbon steel brazing on various counts, specifically concerning the cleanliness of your metal, the joint design of the assembly, the purity from the furnace atmosphere, and also the length on the cooling method. To find out extra about treating stainless steel, speak to a heat treating provider that specializes in chromium alloys currently.