Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Tomoaki Hamaguchi

Hirokazu Okada

Hiroyuki Hirata

Hiroyuki Semba

Kana Jotoku

Toshihide Ono

Katsuki Tanaka

Atsuro Iseda

Mitsuru Yoshizawa

Shinnosuke Kurihara

The present invention provides a welding material for ferritic heat-resistant steel, a welded joint for ferritic heat-resistant steel, and a method for producing the welded joint for to form a weld metal having a high creep strength and a high toughness in welding a ferritic heat-resistant steel that contains B. The welding material for ferritic heat-resistant steel has a chemical composition containing, in mass %, C: 0.06 to 0.10%, Si: 0.1 to 0.4%, Mn: 0.3 to 0.7%, Co: 2.6 to 3.4%, Ni: 0.01 to 1.10%, Cr: 8.5 to 9.5%, W: 2.5 to 3.5%, Nb: 0.02 to 0.08%, V: 0.1 to 0.3%, Ta: 0.02 to 0.08%, B: 0.007 to 0.015%, N: 0.005 to 0.020%, with the balance being Fe and impurities, and satisfying Formula (1):0.5&#x2264;Cr+6Si+1.5W+11V+5Nb+10B&#x2212;40C&#x2212;30N&#x2212;4Ni&#x2212;2Co&#x2212;2Mn&#x2264;10.0&#x2003;&#x2003;(1).

Welding material for ferritic heat-resistant steel, welded joint for ferritic heat-resistant steel, and method for producing welded joint for ferritic heat-resistant steel

A high Cr austenitic stainless steel with a chemical composition consisting of in terms of % by mass, 0.03 to 0.12% of C, 0.10 to 1.00% of Si, 0.10 to 3.00% of Mn, 0.030% or less of P, 0.020% or less of S, 21.50 to 28.00% of Cr, more than 26.00 and not more than 35.00% of Ni, more than 2.00 and not more than 5.00% of W, 0.80% or less of Co, 0.01 to 0.70% of V, 0.15 to 1.00% of Nb, 0.001 to 0.040% of Al, 0.0001 to 0.0100% of B, 0.010 to 0.400% of N, 0.001 to 0.200% of Zr, 0.001 to 0.200% of Nd, 0.001 to 0.200% of Ta, 0.020 to 0.200% of Ta+0.8Nd+0.5Zr, 0.025% or less of Ti+Sn+Sb+Pb+As+Bi, 0.0090% or less of O, and a remainder consisting of Fe and impurities.

High Cr-based austenitic stainless steel

A Ni-based alloy includes, as a chemical composition, C, Si, Mn, Cr, Mo, Co, Al, Ti, B, P, S, and a balance consisting of Ni and impurities. The average grain size d is 10 &#x3bc;m to 300 &#x3bc;m, when the average grain size d is an average grain size in unit of &#x3bc;m of a &#x3b3; phase included in a metallographic structure of the Ni-based alloy. Precipitates with a major axis of 100 nm or more are absent in the metallographic structure. An area fraction &#x3c1; is f2 or more, when the area fraction &#x3c1; and the f2 are expressed by using the average grain size d and amounts in mass % of each element in the chemical composition.

Ni-based alloy

Growing community of inventors

Tokyo, Japan

Tomoaki Hamaguchi