Abstract: A welding method wherein the root gap aperture displacement is measured before welding begins, and a welding material having a Mn/S ratio and a Mn/Si ratio compatible with the measured root gap aperture displacement is selected from gas-shielded arc welding materials. Gas-shielded arc welding is then performed using the selected welding material.

Abstract: A welding method wherein the root gap aperture displacement is measured before welding begins, and a welding material having a Mn/S ratio and a Mn/Si ratio compatible with the measured root gap aperture displacement is selected from gas-shielded arc welding materials. Gas-shielded arc welding is then performed using the selected welding material.

Abstract: A radiation-sensitive resin composition comprising an alkali-soluble novolak resin and a 1,2-quinonediazide compound, wherein the alakli-soluble novolak resin comprises a mixture of:95-50 parts by weight of Resin A having a standard polystyrene-reduced weight-average molecular weight of 2,000-20,000 ?Resin A is at least one resin selected from the group consisting of a resin obtained by polycondensation of m-cresol and at least one phenol represented by the structural formula (I) or (I'): ##STR1## wherein m is 2 or 3, with at least one aldehyde and a resin obtained by polycondensation of m-cresol, p-cresol and at least one phenol represented by the above structural formula (I) or (I') with at least one aldehyde! and5-50 parts by weight of Resin B having a standard polystyrene-reduced weight-average molecular weight of 200-2,000 ?Resin B is a resin obtained by polycondensation of at least one phenol represented by the structural formula (II): ##STR2## wherein n is 0, 1, 2 or 3, with at least one aldehyde!.

Abstract: A radiation-sensitive resin composition comprising an alkali-soluble novolak resin and a 1,2-quinonediazide compound, wherein the alakli-soluble novolak resin comprises a mixture of:95-50 parts by weight of Resin A having a standard polystyrene-reduced weight-average molecular weight of 2,000-20,000 [Resin A is at least one resin selected from the group consisting of a resin obtained by polycondensation of m-cresol and at least one phenol represented by the structural formula (I) or (I'): ##STR1## wherein m is 2 or 3, with at least one aldehyde and a resin obtained by polycondensation of m-cresol, p-cresol and at least one phenol repreented by the above structural formula (I) or (I') with at least one aldehyde] and5-50 parts by weight of Resin B having a standard polystyrene-reduced weight-average molecular weight of 200-2,000 [Resin B is a resin obtained by polycondensation of at least one phenol represented by the structural formula (II): ##STR2## wherein n is 0, 1, 2 or 3, with at least one aldehyde].