US2015090378A1PendingUtilityA1

Method of hot-shaping and hardening a sheet steel blank

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Assignee: ERIKSSON KATARINAPriority: Jul 6, 2011Filed: Jul 4, 2012Published: Apr 2, 2015
Est. expiryJul 6, 2031(~4.9 yrs left)· nominal 20-yr term from priority
Inventors:Katarina ErikssonJan Larsson
C21D 8/02C22C 38/04C22C 38/02C21D 8/0247C21D 8/0221C21D 2211/002C21D 1/673C21D 1/20C21D 9/0068B21D 22/022C21D 1/19B21D 22/02C21D 9/46C21D 8/0205
37
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Claims

Abstract

A sheet steel blank is heated to the austenite range and formed in a cooled tool pair that rapidly cools the formed product until the product's temperature drops somewhat below the temperature Ms for the start of the formation of martensite. The cooling is rapidly interrupted and the product's temperature is raised until it exceeds Ms and is maintained there until the material comes to contain more than 50% by volume bainite. The short time under the Ms temperature favours the formation of bainite and shortens the holding time.

Claims

exact text as granted — not AI-modified
1 . A method of hot shaping and hardening a sheet steel blank by forming the blank, heated to the austenite range, in a tool pair that rapidly cools the formed product,
 characterized in   that the formed product is cooled until the product's temperature drops below the temperature for the start of the formation of martensite, Ms, and the product's temperature is then raised until it exceeds the temperature for the start of the formation of martensite and is maintained hot so that bainite is formed.   
     
     
         2 . The method according to  claim 1 , characterized in that the raised heat is maintained for a holding time of 1-20 minutes. 
     
     
         3 . The method according to  claim 1 , characterized in that temperatures are selected so that the material comes to contain more than 50% by vol. bainite. 
     
     
         4 . The method according to  claim 1 , characterized in that the formed product is subsequently worked directly in the tool pair. 
     
     
         5 . The method according to  claim 1 , characterized in that the material is cooled and shaped in a first tool pair down to a temperature exceeding Ms and the shaped blank is then moved to a second tool pair and cooled further to a temperature below Ms with this tool pair as a fixture. 
     
     
         6 . The method according to  claim 5 , characterized in that the formed product is subsequently worked in the first tool pair. 
     
     
         7 . The method according to  claim 5 , characterized in that the formed product is subsequently worked in the second tool pair. 
     
     
         8 . The method according to  claim 2 , characterized in that the formed product is subsequently worked directly in the tool pair. 
     
     
         9 . The method according to  claim 3 , characterized in that the formed product is subsequently worked directly in the tool pair. 
     
     
         10 . The method according to  claim 2 , characterized in that the material is cooled and shaped in a first tool pair down to a temperature exceeding Ms and the shaped blank is then moved to a second tool pair and cooled further to a temperature below Ms with this tool pair as a fixture. 
     
     
         11 . The method according to  claim 3 , characterized in that the material is cooled and shaped in a first tool pair down to a temperature exceeding Ms and the shaped blank is then moved to a second tool pair and cooled further to a temperature below Ms with this tool pair as a fixture. 
     
     
         12 . The method according to  claim 4 , characterized in that the material is cooled and shaped in a first tool pair down to a temperature exceeding Ms and the shaped blank is then moved to a second tool pair and cooled further to a temperature below Ms with this tool pair as a fixture. 
     
     
         13 . The method according to  claim 10 , characterized in that the formed product is subsequently worked in the first tool pair. 
     
     
         14 . The method according to  claim 11 , characterized in that the formed product is subsequently worked in the first tool pair. 
     
     
         15 . The method according to  claim 12 , characterized in that the formed product is subsequently worked in the first tool pair. 
     
     
         16 . The method according to  claim 10 , characterized in that the formed product is subsequently worked in the second tool pair. 
     
     
         17 . The method according to  claim 11 , characterized in that the formed product is subsequently worked in the second tool pair. 
     
     
         18 . The method according to  claim 12 , characterized in that the formed product is subsequently worked in the second tool pair.

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