Steel for Hot Tooling, and Part Produced From Said Steel, Method for the Production Thereof, and Uses of the Same

Abstract

The invention relates to steel for hot tooling, the composition of said steel being made up of the following weight percentages: 0.30%=C=0.39%, 4.00%=Cr=6.00%, traces=Si=0.50%, traces=Mn=0.80%, traces=W=1.45%, traces=Co=2.75%, 0.80%=Ni=2.80%, 1.50%=Mo=2.60% with 1.50%=Mo+0.65W=3.20%, 0.55%=V=0.80%, with 0.65=K=0.65, where K=K2−K1 and K2=0.75×(Ni 0.60), K1=1.43×(V0.40)+0.63×[(Mo+0.65W) 1.20], traces=Al=0.080%, traces=S=0.0040%, traces=P=0.0200%, traces=Ti=0.05%, traces=Zr=0.05%, traces=Nb=0.08%, traces=N=0.040%, 10P+As+5Sb+4Sn=0.21%, traces=O=30 ppm, the remainder being iron and inevitable impurities. The invention also relates to a part produced from said steel, to the method for the production thereof, and to the use of the same.

1 . Steel for hot tooling, having a composition in percentages by weight:
 0.30%≦C≦0.39%   4.00%≦Cr≦6.00%   traces≦Si≦0.50%   traces≦Mn≦0.80%   traces≦W≦1.45%   traces≦Co≦2.75%   0.80%≦Ni≦2.80%   1.50%≦Mo≦2.60% with 1.50%≦Mo+0.65W≦3.20%   0.55%≦V≦0.80%   with −0.65≦K≦0.65
   where  K=K 2− K 1 
   and  K 2=0.75×(Ni−0.60) 
     K 1=1.43×(V−0.40)+0.63×[(Mo+0.65W)−1.20] 
   traces≦Al≦0.080%   traces≦S≦0.0040%   traces≦P≦0.0200%   traces≦Ti≦0.05%   traces≦Zr≦0.05%   traces≦Nb≦0.08%   traces≦N≦0.040%
   10P+As+5Sb+4Sn≦0.21% 
   traces≦O≦30 ppm   the rest being iron and inevitable impurities.   
     
     
         2 . Steel according to  claim 1 , characterised in that 0.33%≦C≦0.38%. 
     
     
         3 . Steel according to  claim 1 , characterised in that traces≦Si≦0.40%. 
     
     
         4 . Steel according to  claim 1 , characterised in that traces≦Mn≦0.60%. 
     
     
         5 . Steel according to  claim 1 , characterised in that 4.6%≦Cr≦6.0%. 
     
     
         6 . Steel according to  claim 1 , characterised in that 1.60%≦Mo≦2.00% and 1.60%≦Mo+0.65 W≦2.20%. 
     
     
         7 . Steel according to  claim 1 , characterised in that traces≦Al≦0.030%. 
     
     
         8 . Steel according to  claim 1 , characterised in that traces≦S≦0.0010%. 
     
     
         9 . Steel according to  claim 1 , characterised in that traces≦P≦0.0080%. 
     
     
         10 . Steel according to  claim 1 , characterised in that traces≦Ti≦0.01%. 
     
     
         11 . Steel according to  claim 1 , characterised in that traces≦Zr≦0.02%. 
     
     
         12 . Steel according to  claim 1 , characterised in that traces≦Nb≦0.01%. 
     
     
         13 . Steel according to  claim 1 , characterised in that traces≦N≦0.01%. 
     
     
         14 . Steel according to  claim 1 , characterised in that 10P+As+5Sb+4Sn≦0.10%. 
     
     
         15 . Steel according to  claim 1 , characterised in that traces≦O≦15 ppm. 
     
     
         16 . Steel according to  claim 1 , characterised in that −0.35≦K≦0.35. 
     
     
         17 . Steel according to  claim 1 , characterised in that
 0.335%≦C≦0.375%   1.50%≦Ni≦2.10%   1.60%≦Mo+0.65 W≦2.20% with 1.60%≦Mo≦2.00%   0.62%≦V≦0.75%.   
     
     
         18 . Steel according to  claim 1 , characterised in that
 0.335%≦C≦0.375%   2.00%≦Ni≦2.40%   1.80%≦Mo+0.65W≦2.90% with 1.80%≦Mo≦3.40% and W≦0.90%   0.66%≦V≦0.76%.   
     
     
         19 . Steel according to  claim 1 , characterised in that
 0.335%≦C≦0.375%   0.90%≦Ni≦1.50%   1.50%≦Mo+0.6W≦1.90% with W≦0.40%   0.55%≦V≦0.63%.   
     
     
         20 . Steel according to  claim 1 , characterised in that: 0.335%≦C≦0.375%, 4.60%≦Cr≦6.00%, traces≦Si≦0.40%, traces≦Mn≦0.60%, traces≦W≦1.45%, traces≦Co≦2.75%, 1.50%≦Ni≦2.10%, 1.60%≦Mo+0.65 W≦2.20% with 1.60%≦Mo≦2.00%, 0.62%≦V≦0.75%, with −0.35≦K≦0.35, traces≦Al≦0.030%, traces≦S≦0.0010%, traces≦P≦0.0080%, traces≦Ti≦0.011%, traces≦Zr≦0.02%, traces≦Nb≦0.01%, traces≦N≦0.01%, traces≦O≦15 ppm. 
     
     
         21 . Method of manufacture of a steel part, characterised in that the said part is prepared from a steel according to  claim 1 , and in that it is subjected to an austenisation within the temperature range from 1000 to 1050° C., followed by quenching. 
     
     
         22 . Method according to  claim 21 , characterised in that the austenisation takes place in the range from 1015 to 1040° C. 
     
     
         23 . Method according to  claim 21 , characterised in that after the quenching the part is subjected to at least two temperings within the temperature range from 550 to 650° C., giving the said part a hardness of 42 to 52 HRC. 
     
     
         24 . Part made from steel obtained by the method according to  claim 21 , characterised in that it is a part for tooling for hot shaping. 
     
     
         25 . Part according to  claim 24 , characterised in that the said part has a thickness greater than or equal to 200 mm. 
     
     
         26 . Part according to  claim 24 , characterised in that it is a mould or a die for founding under pressure light alloys or cuprous alloys. 
     
     
         27 . Part according to  claim 24 , characterised in that it is a forging tool. 
     
     
         28 . Part according to  claim 24 , characterised in that it is a forging die. 
     
     
         29 . Part according to  claim 24 , characterised in that it is a tool for drilling or for rolling of steel tubes. 
     
     
         30 . Part according to  claim 24 , characterised in that it is a tool for shaping glass. 
     
     
         31 . Part according to  claim 24 , characterised in that it is a tool for shaping plastics materials. 
     
     
         32 . Part according to  claim 24 , characterised in that it is produced from a steel wherein
 0.335%≦C≦0.375%   2.00%≦Ni≦2.40%   1.80%≦Mo+0.65W≦2.90% with 1.80%≦Mo≦3.40% and W≦0.90%   0.66%≦V≦0.76%; and   in that it is an extrusion die or a mould for founding aluminium alloy.   
     
     
         33 . Use of a part according to  claim 24 , characterised in that the said part is made from a steel wherein
 0.335%≦C≦0.375%   2.00%≦Ni≦2.40%   1.80%≦Mo+0.65W≦2.90% with 1.80%≦M≦3.40% and W≦0.90%   0.66%≦V≦0.76%; and   in that its working temperature at the surface remains below 680° C.   
     
     
         34 . Use of a part according to  claim 24 , characterised in that the said part is made from a steel wherein
 0.335%≦C≦0.375%   0.90%≦Ni≦1.50%   1.50%≦Mo+0.6W≦1.90% with W≦0.40%   0.55%≦V≦0.63%; and   in that its surface temperature in operation remains below 770° C.