Abstract: The invention relates to a cutting tool containing 25-33 percent by weight of Co and certain amounts of W, Mo, C, B, Zr, Si, Mn, Cr, Ni and Fe containing normal contaminants, W + 2Mo being equal to 20-40 percent by weight, the structure of the tool consisting of a martensitic matrix having a grain size of 5-70 .mu.m, determined as austenite grain size, containing 5-15 percent by volume of an intracrystalline, very homogeneously distributed fine-disperse phase consisting of an intermetallic compound of Fe, Co, W and/or Mo and, between the grains of the base mass, 20-30 percent by volume of a primarily precipitated phase mainly consisting of the same intermetallic compound but having a predominant grain size of 1-2 .mu.m.
Abstract: The invention relates to a process for the manufacture of a chain having an ultimate tensile strength of at least 90 kg/mm.sup.2 and an impact strength at .+-. 0.degree. C of at least 2.8 kgm starting from a steel ingot containing C, Si, Mn, Cr, Mo, N, Al, Nb (Cb), and Fe in certain amounts, said ingot being hot rolled to a rod of a dimension suitable for use in a chain, cut into pieces of adjusted length and after resistance heating to 700.degree.-900.degree. C said pieces being bent and flash-butt welded to connected links of a chain, said chain being then normalized by heating to a temperature of 700.degree.-900.degree. C and then cooled in air. The invention also covers chains prepared by the process.
Type:
Grant
Filed:
December 22, 1975
Date of Patent:
January 11, 1977
Assignee:
Stora Kopparbergs Bergslags Aktiebolag
Inventors:
Barbro Marie Rohlin, Sten Lennart Bergh, Gustav Nils Herman Westerberg
Abstract: The invention relates to a method of combined production of electrical energy and crude iron, comprising reducing iron oxides while keeping the temperature below the melting point of the crude iron during a pre-reduction and above said melting point during a final reduction. The pre-reduction is made by introducing carbonaceous material and the material containing iron oxides into a fluid bed containing solid carbonaceous material, producing reducing gases in the fluid bed by partial combustion of the carbonaceous material with air/or oxygen gas, pre-reducing the iron oxides by said reducing gases until the material has achieved a metallization degree of 30-80 %, most of the heat requirement of the pre-reduction being covered by said combustion. The pre-reduced material is finally reduced and molten by being brought into contact with carbon, and the heat requirement of this final reduction and melting process is covered by electric heating.
Type:
Grant
Filed:
July 31, 1974
Date of Patent:
October 12, 1976
Assignee:
Stora Kopparbergs Bergslags Aktiebolag
Inventors:
Per Harald Collin, Folke Karl Evald Johansson
Abstract: In the manufacture of saw blades a metal block is first produced, having a central portion consisting of cutting tool steel. The block is now flattened to form a sheet in which the cutting tool steel forms a central strip. The sheet is now divided to form two blades, each blade having an edge portion consisting of the cutting tool steel. Saw teeth are finally cut in said edge portion.
Type:
Grant
Filed:
March 5, 1975
Date of Patent:
January 6, 1976
Assignee:
Stora Kopparbergs Bergslags Aktiebolag
Inventors:
Bo Erik Gunnar Berggren, Nils Torsten Strandberg