Aluminum alloy plate excellent in press formability and continuous resistance spot weldability and method for production thereof

Abstract

The present invention provides an aluminum alloy sheet having excellent compression formability and continuous resistance spot weldability and a method for producing the same. The aluminum alloy plate includes: 0.3-1.0% magnesium by mass fraction, 0.3-1.2% silicon, 0.10-1.0% iron and 0.05-0.5% manganese; here iron + manganese ≥ 0.2%; the rest includes aluminum and unavoidable impurities, where the average recrystallized particle size is 25 μm or less, and the interlayer compound with a circumferential equivalent diameter of 1-6 μm is at least 5000 particles / mm2. It may further contain 0.5-1.0% copper, 0.1-0.4% zinc, 0.05% or less titanium or 0.05% or less titanium and 0.01% or less boron. The present invention also provides a method for preparing an aluminum alloy plate, which includes pouring the melt of the above composition into a relatively rotating belt casting machine that is forced to cool; when pouring the melt, the cooling rate is 40-90°C / sec to form a 5-10mm thick the slab; stretching the slab from the opposite side of the melt pouring sprue; direct rolling or winding into coils; followed by solution heat treatment.

Description

technical field [0001] The present invention relates to an aluminum alloy sheet excellent in press formability and continuous resistance spot weldability, which is used as a structural material and assembled by resistance spot welding before or after molding to form outer panels of products such as home appliances or automobiles. Background technique [0002] Structural materials and outer panels of products such as household appliances and automobiles are first molded and then resistance spot welded to assemble the product. [0003] After compression molding, Al-Mg-Si type alloy sheet (JIS6000) exhibits quite excellent surface quality, so it is used as various types of panels and structural materials, but due to the diversity of product shapes, it is required to have good compression molding sex. [0004] Additionally, there is a need to increase continuous resistance spot welding capabilities to reduce the time during which electrodes are replaced in resistance spot weldi...

AI Technical Summary

Problems solved by technology

[0007] Japanese Patent Application First Publication No. S62-207851 describes a casting process technique with a cooling rate of at least 100°C / sec, the size of the crystallized intermetallic compounds in the casting is small, and the result is the amount of relatively large compounds that affect the recrystallized grain size Insufficient, so the particle size after solution heat treatment is large, so the moldability is reduced, and the number of continuous resistance spot welding is reduced

[0008] Japanese Patent Application First Publication No. 2001-262264 discloses a technique using a continuous casting process with a minimum cooling rate of 10°C / sec for casting, but in the examples, a maximum cooling rate of 30°C / sec was used, since the cooling rate is slow , the size of intermetallic compounds crystallized in casting is large, and as a result, the number of relatively large compounds that affect the recrystallized grain size is insufficient, so that the grain size after solution heat treatment is large, reducing the number of molding formability and continuous resistance spot welding