| 摘要 |
<p>Chisel is inserted in the driving bush of the hammer, and is made of a hardened and tempered alloy steel with compsn. 0.25-0.7% C, 0.15-2.0% Si, 0.3-2.0% Mn, 0.5-2.0% CR, 0.15-0.5% Mo, and 0.05-0.25% V. The chisel is hardened and tempered throughout its entire cross-section to obtain a tensil strength (UTS) of 1200-1600 N/mm2. Chisel is pref. made of the steel 42 Cr Mo 4; or 50 Cr Mo 4; or 50 Cr V 4; and is used e.g. for breaking up stone or concrete; or for breaking up hot slags etc. in steelmaking- or smelting- works. As compared with chisels made of conventional materials, the invention uses a lower alloy content reducing material cost, but the working life of the chisels is increased up to twice the previous life, and fatigue fractures are virtually nil as compared to 15-20% for conventional chisels.</p> |
