Martensitically hardenable steel and use thereof, in particular for producing a screw

Abstract

A steel comprising 0.07 to 0.14 wt. % of carbon, 13 to 15 wt. % of chromium, 1.3 to 1.7 wt. % of molybdenum, 1.5 to 2.0 wt. % of nickel and 1.0 to 1.5 wt. % of manganese and use of the steel for producing screws is provided.

1 . A method for producing a shaped body, the method comprising producing a blank comprising a steel with 0.07 to 0.14 wt % carbon, 13 to 15 wt % chromium, 1.3 to 1.7 wt % molybdenum, 1.5 to 2.0 wt % nickel and 1.0 to 1.5 wt % manganese. 
     
     
         2 . The method according to  claim 1 , including case-hardening the blank with nitrogen from the gas phase. 
     
     
         3 . The method according to  claim 2 , including the case-hardening the blank with nitrogen from the gas phase in combination with carburizing the blank with carbon from the gas phase. 
     
     
         4 . The method according to  claim 2 , including processing the blank, wherein case-hardening the blank is performed subsequent to processing the blank. 
     
     
         5 . The method according to  claim 1 , including deep-freezing the blank at temperatures below minus 80° C. and subsequently annealing the blank at temperatures between 150° C. and 500° C. 
     
     
         6 . The method according to  claim 1 , wherein the shaped body is a screw shape. 
     
     
         7 . The method according to  claim 6 , including local induction hardening of a tip portion of the screw shape. 
     
     
         8 . A steel comprising 0.07 to 0.14 wt % carbon, 13 to 15 wt % chromium, 1.3 to 1.7 wt % molybdenum, 1.5 to 2.0 wt % nickel and 1.0 to 1.5 wt % manganese. 
     
     
         9 . A screw produced using the steel of  claim 8 . 
     
     
         10 . A screw at least partially comprising a steel obtainable in the method according to  claim 1 . 
     
     
         11 . A screw according to  claim 10 , having a ratio of an outside diameter (d) of a thread of the screw to a thread pitch (p) of the thread is in the range of 1 to 2. 
     
     
         12 . The method according to  claim 2 , comprising case-hardening the blank with nitrogen from the gas phase at temperatures between 1,000° C. and 1,150° C. 
     
     
         13 . The method according to  claim 2 , comprising case-hardening the blank with nitrogen from the gas phase at a nitrogen partial pressure between 0.05 and 0.3 bar. 
     
     
         14 . The method according to  claim 12 , comprising case-hardening the blank with nitrogen from the gas phase at a nitrogen partial pressure between 0.05 and 0.3 bar. 
     
     
         15 . The method according to  claim 3 , including processing the blank, wherein case-hardening the blank is performed subsequent to processing the blank. 
     
     
         16 . The method according  claim 2 , including deep-freezing the blank at temperatures below minus 80° C. and subsequently annealing the blank at temperatures between 150° C. and 500°. 
     
     
         17 . The method according  claim 3 , including deep-freezing the blank at temperatures below minus 80° C. and subsequently annealing the blank at temperatures between 150° C. and 500°. 
     
     
         18 . The method according  claim 4 , including deep-freezing the blank at temperatures below minus 80° C. and subsequently annealing the blank at temperatures between 150° C. and 500°. 
     
     
         19 . The method according to  claim 2 , wherein the shaped body is a screw shape. 
     
     
         20 . The screw according to  claim 11 , wherein the ratio of the outside diameter of the thread to the thread pitch is in the range of 1.2 to 1.45.