Mechanical clinch joining component and method for manufacturing same

Abstract

In one aspect of the present invention, a mechanical clinched joint component is a mechanical clinched joint component formed of two or more steel sheets, where the component includes at least one joint portion having a peel strength of 0.200 kN/mm or greater, and the component has a hardness of 360 Hv or greater. A method for manufacturing the component sequentially includes heating the two or more steel sheets to an Ac3 temperature or above, and performing mechanical clinch joining so that a carbon equivalent Ceq of the steel sheets, and a bottom-dead-center holding time t and a joining start temperature T during mechanical clinch joining satisfy relationships of equation (1) below and of equation (2) below: Ceq×(0.00209×t+0.000731×T−0.0365)≥0.200   (1), and Ceq≥0.00071×T+0.993   (2).

1 . A mechanical clinched joint component formed of two or more steel sheets, wherein:
 the component comprises at least one joint portion having a peel strength of 0.200 kN/mm or greater; and   the component has a hardness of 360 Hv or greater.   
     
     
         2 . A method for manufacturing the mechanical clinched joint component according to  claim 1 , the method sequentially comprising:
 heating the two or more steel sheets to an Ac3 temperature or above; and   performing mechanical clinch joining so that a carbon equivalent Ceq of the steel sheets, and a bottom-dead-center holding time t mid a joining start temperature T during mechanical clinch joining satisfy relationships of equation (1) below and of equation (2) below:
   Ceq×(0.00209×t+0.000731×T−0.0365)≥0.200   (1)
 
   Ceq≥−0.00071×T+0.993   (2)
 
   where Ceq represents the carbon equivalent (mass %) of the steel sheets calculated by equation (3) below, t represents the bottom-dead-center holding time (second), and T represents the joining start temperature (° C.), wherein, if a value of Ceq differs in the two or more steel sheets, a lowest value of Ceq is used,
   Ceq=C+(1/6)×Mn+(1/24)×Si+(1/40)×Ni+(1/5)×Cr+(1/4)×Mo+(1/14)×V   (3)
 
   where each of element names represents a content in mass % in the steel sheets, and represents zero if that element is not contained.   
     
     
         3 . The method for manufacturing the mechanical clinched joint component according to  claim 2 , wherein the two or more steel sheets each has a constituent composition in mass % satisfying:
 C: 0.15 to 0.4%,   Si: more than 0% to 2% or less, and   at least one of Mn and Cr: 1.0 to 5.0% in total, and further satisfying:   Ti: 0% or more to 0.10% or less,   B: 0% or more to 0.005% or less,   Al: 0% or more to 0.5% or less,   Mo: 0% or more to 1% or less,   Cu: 0% or more to 0.5% or less,   Ni: 0% or more to 0.5% or less,   Nb: 0% or more to 0.10% or less,   V: 0% or more to 0.10% or less, and   Zr: 0% or more to 0.10% or less.   
     
     
         4 . The method for manufacturing the mechanical clinched joint component according to  claim 2 , wherein hot press forming is also performed in the step of performing mechanical clinch joining. 
     
     
         5 . The method for manufacturing the mechanical clinched joint component according to  claim 2 , wherein the step of performing mechanical clinch joining is performed a plurality of times.