레이저 용접이음의 피로강도

Abstract

점용접은 승용차 차체 용접법으로 이제까지 널리 사용되었으나 최근에 일부 점용접이 레이저 용접으로 대체되었고 적용사례가 점점 많아지고 있다. 레이저 용접은 점용접에 비하여 생산속도, 생산제품의 칫수정확도, 경량화 특성 등에서 뛰어나다. 이 논문에서는 레이저 용접의 정적강도와 피로강도를 실험과 해석적인 방법으로 점용접과 비교하였다. 정적강도에 대하여 레이저 용접조건의 영향을 조사하여 정적강도 예측식을 구하였다. 피로강도에 대하여 레이저 용접과 점용접 모두 용접부 가장자리 최대스트레인으로 정리하니 서로 일치하였다.

Spot-welded joints have been widely used in passenger car industry. Recently, some spot-welded joints are replaced by laser-weld joints and such applications are increasing. Laser-welded joints are superior to spot-weld joints in production speed, accuracy of the product and production of light-weight structure.

In this paper, both the static strength and fatigue strength of laser-welded joints are compared to those of spot-welded joints experimentally and analytically.

The influence of change in welding conditions on the static strength are investigated from the results of tensile tests. The equation to predict the static strength can be constructed from the above influence factors.

From the finite element solution, the maximum strains at the edge of the weld on surface of the specimens are calculated. The fatigue strength is inversely proportional to the maximum strain during the load cycle.

Spot-welded joints have been widely used in passenger car industry. Recently, some spot-welded joints are replaced by laser-weld joints and such applications are increasing. Laser-welded joints are superior to spot-weld joints in production speed, accuracy of the product and production of light-weight structure.

In this paper, both the static strength and fatigue strength of laser-welded joints are compared to those of spot-welded joints experimentally and analytically.

The influence of change in welding conditions on the static strength are investigated from the results of tensile tests. The equation to predict the static strength can be constructed from the above influence factors.

From the finite element solution, the maximum strains at the edge of the weld on surface of the specimens are calculated. The fatigue strength is inversely proportional to the maximum strain during the load cycle.