THE EMPHASIS OF PHASE TRANSFORMATIONS AND ALLOYING CONSTITUENTS ON HOT CRACKING SUSCEPTIBILITY OF TYPE 304L AND 316L STAINLESS STEEL WELDS

• Published in: International journal of engineering science and technology Vol. 4; no. 5; p. 2206
• Main Authors: Saluja, Rati, Moeed, K M
• Format: Journal Article
• Language: English
• Published: 01.05.2012
• Subjects: Alloy steels; Alloying; Austenitic stainless steels; Cracking (fracturing); Ferrite; Fracture mechanics; Heat resistant steels; Silicon; Weld defects
• ISSN: 0975-5462; 0975-5462

Hot cracking is a significant problem due to transformation of retained ferrite into sigma phase, which results preferential corrosion of ferrite. The Hot Cracking Susceptibility is high for fully austenitic compositions but specimens with 5 to 30% ferrite were quite resistant to cracking. Hot cracking in 304L and 316L is amplified by low-melting eutectics containing impurities such as S, P, Si, N. It could be diminished by small increase in C, N, Cr, Ni, Si or by substantial increase in Mn content. To avoid formation of excess ferrite and to control cracking, weld metal should have a ferrite content of atleast 3 to 5 ferrite number, the present investigation evaluates the hot crack susceptibility of 304L and 316L type austenitic stainless steels to the chemical composition of the alloying material. The propensity for hot cracking is determined primarily by the hot cracking susceptibility factor. To determine the suitable composition and the corresponding ferrite numbers for type 304L and 316L the Schaeffler-DeLong diagram is used.