Flash butt welding member and flash butt welding method for providing wheel rim weld part with excellent formability
AssigneePosco
InventorsGyu-Yeol Bae, Ho-Soo Kim
Life of this patent
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Abstract
Provided are a flash butt welding member and a flash butt welding method for providing a wheel rim weld part with excellent formability. The flash butt welding member of the present invention satisfies that a weld part has a hardness of 220-270 Hv, and d<0.25T, when d is the closest distance between fine-grained heat affected zones (HAZ) formed at the left and right of the weld part while facing each other and T is the thickness of a weld base metal, and satisfies L/T>2, when the total length of an upset part constituting the weld part is L.
Claims5
A welding member having formability for a wheel rim weld portion, the welding member comprising:
- a weld portion obtained by flash butt welding two steel plates using an electrode;
- and
- a first fine-grained heat affected zone (HAZ) and a second fine-grained HAZ on the left and right, respectively, of the weld portion in a facing manner,
- wherein:
- a hardness of the weld portion is 220 to 270 Hv, the weld portion satisfies d<0.25 Tin which d is a shortest distance between the first fine-grained HAZ and the second fine-grained HAZ and T is a thickness of a welding target material,
- the weld portion satisfies 2<L/T in which L is an overall length of an upset part forming the weld portion,
- and an average grain diameter of the fine-grained HAZ is 10 μm or less.
A flash butt welding method comprising:
- pre-heating a weld target surface of two steel plates including applying a first current that is 30 to 40% of a short-circuit current,
- flash butt welding the pre-heated weld target surface of the two steel plates via an electrode and subsequently upset heating to form an upset heated weld portion,
- cooling the upset heated weld portion to form a cooled weld portion, and
- and post-heating the cooled weld portion to form a weld portion,
- wherein the weld portion obtained has hardness of 220 to 270 Hv, satisfies d<0.25 T in which d is a shortest distance between fine-grained heat affected zones (HAZs) formed on the left and right of the weld portion in a facing manner and T is a thickness of a welding target material, and satisfies 2<L/T in which L is an overall length of an upset part forming the weld portion.
Dependencies are inferred from the claim text.