Abstract: A hollow golf club head made of a metallic material. The golf club head has a three piece structure, a main head body, face, and crown. The main head body and the crown are formed by casting or press-forming, the face is formed by press-forming, and these are joined together by welding. The metallic material used is selected from a steel material group of martensite deposition hardening-type stainless steel, maraging steel, and maraging stainless steel. Only a material having a specific gravity of 7.7 or higher is used, and the head body has a volume of 280-320 cc and a weight of 180-205 g. The golf club head enables increasing the meet rate, has design freedom, exhibits excellent processability, and can be manufactured at a low cost.

Abstract: A hollow golf club head made of a metallic material. The golf club head has a three piece structure of a main head body, face and crown. The main head body and the crown are formed by casting or press-forming, the face is formed by press-forming, and these are joined together by welding. The metallic material used is selected from a steel material group of martensite deposition hardening-type stainless steel, maraging steel, and maraging stainless steel. Only a material having a specific gravity of 7.07 or higher is used, and the head body has a volume of 280-320 cc and a weight of 180-205 g. The golf club head enables increasing the meet rate, has design freedom, exhibits excellent processability, and can be manufactured at a low cost.

Abstract: Described herein is high strength steels used for bolts containing as alloy elements:0.30%.ltoreq.C.ltoreq.0.50%,Si<0.10%,0.50%.ltoreq.Mn.ltoreq.0.70%,P.ltoreq.0.01%,S.ltoreq.0.01%,0.30%.ltoreq.Cr.ltoreq.1.05%,0.50%.ltoreq.Mo.ltoreq.1.05%,0.01%.ltoreq.al.ltoreq.0.05%,0.0020%.ltoreq.Ti.ltoreq.0.050%, and0.002%.ltoreq.N.ltoreq.0.010%,the elements Si, Mn, P, S, Mo, Al, Ti and N satisfying the relation as follows0.05%.ltoreq.Mo-45P-11S.ltoreq.0.85%7.5Si+1.7Mn.ltoreq.1.85%, and0.020%.ltoreq.10Ti+Al-6N.ltoreq.0.50%;and the balance of Fe and inevitable impurities.The high strength steels used for bolts may optionally contain at least one of Ni and V in the range of0.2%.ltoreq.Ni.ltoreq.1.5% and 0.05%.ltoreq.V.ltoreq.0.15%, respectively.

Abstract: A material for steel wool is disclosed which essentially consists of 0.05 to 0.20% of C, up to 0.10% of Si, 0.50 to 1.30% of Mn, 0.035 to 0.10% of P, up to 0.04% of S,0.05 to 0.15% of N and the balance Fe. In this material, Al.sub.2 O.sub.3 inclusions with sizes not smaller than 3 microns are suppressed to a level not greater than 20 ppm and when the content of the Al.sub.2 O.sub.3 inclusions (3 microns and over) is in the range of 5 to 20 ppm, Al.sub.2 O.sub.3 inclusions with a size ranging from 3 to 10 microns is contained in an amount not smaller than 30% of the total content of Al.sub.2 O.sub.3 inclusions with sizes not smaller than 3 microns.

Abstract: A steel for machine construction having excellent cold forgeability and machinability, the steel having a composition of below 0.6% C, below 0.35% Si, below 1.65% Mn, below 3.5% Ni, below 3.5% Cr, below 0.35% Mn, 0.010-0.10% Al and below 0.002% B, the rest being Fe and impurities with limited contents of Ca in the range of 0.0005-0.05%, S of below 0.12% and Al.sub.2 O.sub.3 inclusion of below 0.002%.