DETERMINATION OF CAUSES OF CRACKING IN WELDING AGE HARDENABLE HIGH TEMPERATURE ALLOYS
Abstract
Tensile, hot ductility, metallographic and weldability studies were conducted to determine the cause of base metal cracking in A-286 weldments.A mechanism for cracking was proposed, based on grain size, interstice formation by grain boundary sliding or Fe2Ti-Fe liquation, embrittlement by Ni3(Al, Ti) general and TiC grain boundary precipitation on insufficiently rapid cooling. The effect of stress on weld metal cracking was studied with variable restraint specimens, and optimum filler wires were evaluated on segmented finger specimens. The strain-age cracking study conducted on Rene' 41 and Inconel X concentrated on the non-equilibrium time between the annealed condition and the aged condition in the 1050 to 1500 F temperature range. Tensile and dilatometric studies indicated a possible transient embrittlement on initial heating. The time, temperature and prior material history dependence of the aging contraction was studied, and based on these results, and metallographic analysis of Inconel X, a mechanism to account for strain-age cracking was developed. The difficulties encountered in developing a valid strain-age cracking specimen are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1962
- Accession Number
- AD0278259
Entities
People
- B.s. Blum