Weldability of IN Steel (Report I)

Abstract

An investigation has been made to study the weldability of various IN Steels. A preliminary test, in which forged and heat treated mild and low alloy IN Steels (IN-1, IN-4 and IN-5) were used as test materials, was followed by the test, where rolled and press-quenched mild and low alloy IN Steels (IN-6, IN-10 and IN-12) and as-rolled IN Steels (IN-A and IN-B) were tested.
Through this investigation, the following conclusions were obtained.
1. Generally, IN Steel has superior weldability compared to other steels of similar chemical composition and strength. This may be due to its ultra-fine grain size.
2. The welded joint of various IN Steels showed good ductility and mechanical properties.
3. The results of maximum hardness test on the HAZ of non-preheated mild IN Steel showed little hazard of weld cracking. Furthermore, the HAZ of low alloy IN Steel has lower hardness than that of comparable commercial steel.
4. A slight raise in transition temperature was obserbed in Charpy impact test on HAZ of IN Steel.
5. NDT of mild and low alloy IN Steels obtained by the NRL drop weight test were betwen-40°C and -75°C.
6. In crack sensitivity tests on low alloy IN Steel (IN-12), no crack was observed in weld metal and HAZ when the specimens were prebeated above 100°C.