| 摘要 |
<p>1,218,799. Sintered steel scrap. G.K.N. SCREWS & FASTENERS Ltd. Oct.30 1969 [Nov. 6, 1968], No. 52605/68. Heading C7D. A sintered body e. g. a pulley is made from turnings, flakes or chips of steel scrap which are embrittled e.g. by carburizing and quenching milled e.g. to particle size 0À05 - 0À3 mm. min. dia., cold pressed e. g. at 5-30 t. s , i., heating the compact e. g. at 800 - 1350‹ C. and then hot pressing the heated compact. Pior to embrittled treatment the scrap is crushed and the embrittled milled scrap may be heat softened e. g. at 700‹ C. in neutral atmosphere prior to cold pressing which may be isostatic pressing. Hot pressing at 40 t.s. i. carried out in a hot or cold die. The carburizing of the scrap to a minimum of 0À35%C is carried out e. g. at 920‹ C. in town gas and propane and water quenched.</p> |
