Method of manufacturing a product from steel and product manufactured according to said method

Abstract

Method of manufacturing a product ( 1, 15 ) from steel, in which a steel with a metastable first phase in which the steel has first properties is manufactured and, by mechanical influences, is transformed into a second, thermodynamically more stable phase with second properties which are at least partly different from the first properties, and, for adapting the product to particular applications, the product ( 1, 15 ) is manufactured locally differently by modification with regard to said phases with different properties. A product according to the invention therefore has, over its surface and/or its thickness, at least two differently adapted areas ( 10, 11 ) with different properties of the steel.

1 . A method of manufacturing a product ( 1 ,  15 ) from steel, in which a steel with a metastable first phase in which the steel has first properties is manufactured and, by mechanical influences, is transformed into a second, thermodynamically more stable phase with second properties which are at least partly different from the first properties, wherein the building product ( 1 ,  15 ) is manufactured locally differently by modification with regard to said phases with different properties.  
     
     
         2 . The method as claimed in  claim 1 , wherein the product ( 1 ,  15 ) is firstly completely or partly transformed into the second phase and wherein the product ( 1 ,  15 ) is then, on at least a part area, subjected to local thermal action in such a way that the steel in this part area is at least partly returned into the first phase.  
     
     
         3 . The method as claimed in  claim 1  or  2 , wherein the metastable first phase is an austenite and the second phase is bainite or martensite.  
     
     
         4 . The method as claimed in  claim 2  or  3 , wherein the local thermal action is carried out inductively.  
     
     
         5 . The method as claimed in  claim 2  or  3 , wherein the local thermal action is carried out by means of a heat source directed locally at the product ( 1 ,  15 ) in a controlled manner.  
     
     
         6 . The method as claimed in  claim 5 , wherein additionally a magnetic field is generated and directed at the product ( 1 ,  15 ).  
     
     
         7 . The method as claimed in  claim 4  or  6 , wherein the thermal action is controlled with the aid of a sensor coil ( 6 ).  
     
     
         8 . A steel product which, by virtue of its composition and its manufacture, has a metastable first phase in which the steel has first properties and which, by mechanical influences, can be transformed into a thermodynamically more stable, second phase with second properties which are at least partly different from the first properties, wherein, over its surface and/or its thickness, it has at least two different areas ( 10 ,  11 ), adapted by modification with regard to said phases, with different properties of the steel.  
     
     
         9 . The steel product as claimed in  claim 8 , wherein the first phase is formed by metastable austenite and the second phase by bainite and/or martensite.  
     
     
         10 . The steel product as claimed in  claim 9 , wherein the first and/or second phase is formed from a mixture of metastable austenite and bainite and/or martensite.  
     
     
         11 . The steel product as claimed in one of  claims 8  to  10 , wherein the first phase and the second phase have different material properties.  
     
     
         12 . The steel product as claimed in  claim 11 , wherein the first phase is not or is only weakly ferromagnetic and the second phase is much more strongly ferromagnetic.  
     
     
         13 . The steel product as claimed in one of  claims 8  to  12 , in the form of a strip-shaped product ( 1 ) with areas ( 10 ,  11 ) which are different with regard to hardness extending over a dimension of the strip.  
     
     
         14 . The steel product as claimed in one of  claims 8  to  12 , in the form of an elongate beam with areas ( 10 ,  11 ) of high and low strength formed in the longitudinal direction.  
     
     
         15 . The steel product as claimed in one of  claims 8  to  12 , in the form of an elongate beam with areas ( 10 ,  11 ) of different strength adjacent to one another in planes located at right angles to the longitudinal direction.