Steel sheet for dissimilar materials weldbonding to aluminum material and dissimilar materials bonded body
First Claim
1. A steel sheet for dissimilar materials weldbonding to an aluminum material, said steel sheet containing, in mass, C:
- 0.02 to 0.3%, Si;
0.2 to 5.0%, Mn;
0.2 to 2.0%, and Al;
0.002 to 0.1%, further one or more of Ti;
0.005 to 0.10%, Nb;
0.005 to 0.10%, Cr;
0.05 to 1.0%, and Mo;
0.01 to 1.0%, and the balance consisting of Fe and unavoidable impurities, whereinthe proportion of the oxide containing Mn and Si by 1 at . % or more in total in the external oxide layer which is newly formed after an original oxide layer having already existed on the surface of said steel sheet is once removed and now exists on the surface of the base steel material of said steel sheet is 50 to 80% in terms of the average proportion of the total length of said oxide to 1 μ
m length of the interface between said base steel material and said external oxide layer nearly in the horizontal direction.
1 Assignment
0 Petitions
Accused Products
Abstract
Disclosed is a steel sheet for dissimilar materials weldbonding to an aluminum material, the steel sheet containing, in mass, C: 0.02 to 0.3%, Si: 0.2 to 5.0%, Mn: 0.2 to 2.0%, and Al: 0.002 to 0.1%, further one or more of Ti: 0.005 to 0.10%, Nb: 0.005 to 0.10%, Cr: 0.05 to 1.0%, and Mo: 0.01 to 1.0%, and the balance consisting of Fe and unavoidable impurities. In the steel sheet, (i) the proportion of the oxide containing Mn and Si by 1 at. % or more in total in the external oxide layer which is newly formed after an original oxide layer having already existed on the surface of the steel sheet is once removed and now exists on the surface of the base steel material of the steel sheet is 50 to 80% in terms of the average proportion of the total length of the oxide to 1 μm length of the interface between the base steel material and the external oxide layer nearly in the horizontal direction, (ii) the proportion of the internal oxide, including oxide at the grain boundary, which exists in the steel region up to the depth of 10 μm from the surface of said base steel material of said steel sheet and contains Mn and Si by 1 at. % or more in total is 3% or more to less than 10% in terms of the average area percentage of said internal oxide in the visual field of 10 μm2 of said steel region, (iii) the proportion of the internal oxide, including oxide at the grain boundary, which exists in the steel region exceeding 10 μm in depth from the surface of said base steel material of said steel sheet and contains Mn and Si by 1 at. % or more in total is 0.1% or less in terms of the average area percentage of said internal oxide in the visual field of 10 μm2 of said steel region.
-
Citations
20 Claims
-
1. A steel sheet for dissimilar materials weldbonding to an aluminum material, said steel sheet containing, in mass, C:
- 0.02 to 0.3%, Si;
0.2 to 5.0%, Mn;
0.2 to 2.0%, and Al;
0.002 to 0.1%, further one or more of Ti;
0.005 to 0.10%, Nb;
0.005 to 0.10%, Cr;
0.05 to 1.0%, and Mo;
0.01 to 1.0%, and the balance consisting of Fe and unavoidable impurities, whereinthe proportion of the oxide containing Mn and Si by 1 at . % or more in total in the external oxide layer which is newly formed after an original oxide layer having already existed on the surface of said steel sheet is once removed and now exists on the surface of the base steel material of said steel sheet is 50 to 80% in terms of the average proportion of the total length of said oxide to 1 μ
m length of the interface between said base steel material and said external oxide layer nearly in the horizontal direction. - View Dependent Claims (2, 3, 4, 5)
- 0.02 to 0.3%, Si;
-
6. A steel sheet, comprising:
-
from 0.02 to 0.3 mass % C; from 0.2 to 5.0 mass % of Si; from 0.2 to 2.0 mass % of Mn; from 0.002 to 0.1% of Al; and one or more selected from the group consisting of Ti in an amount of from 0.005 to 0.10 mass %, Nb in an amount of from 0.005 to 0.10 mass %, Cr in an amount of from 0.05 to 1.0 mass %, and Mo in an amount of from 0.01 to 1.0 mass %; wherein the balance in mass % comprises Fe and unavoidable impurities; wherein mass % is based on the total mass of the steel sheet; wherein the outer surface of the steel sheet is an external oxide layer and the external oxide layer is in direct and continuous contact with an internal oxide layer beneath the external oxide layer; wherein the external oxide layer comprises an oxide phase comprising one or more external oxides wherein the external oxides comprise at least one of Mn and Si in an amount of 1 at. % or more; wherein the oxide phase is from 50 to 80% of the length of a 1 μ
m length of the external oxide layer; andwherein the steel sheet is obtained by removing an original oxide layer and then forming the external oxide layer in a controlled atmosphere comprising an amount of oxygen that is lower than the amount of oxygen present in an original atmosphere in which the original oxide layer was formed. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification