《铝合金建筑型材》GB5237—92已于去年通过审定,与GB5237—85相比,主要技术内容变更如下:1.增加了LD30合金(6061)。2.断面尺寸允许偏差增加了超高精级(与DIN17615相当)。标准明确规定了图样标注的尺寸偏差必须符合高精度或超高精级,未标注的尺寸必须符合普通级。修改后的断面尺寸偏差规定与世界各国标准的规定基本接轨。3.外形尺寸允许偏差、弯曲、扭拧等,均增加了超高精级。4.LD31合全的纵向挤压痕深度改为0.05mm,但与美国标准的规定值仍有差距。5.增加了对型材铸锭的控制,要求型材铸锭必须经过均匀化处理。6.氧化膜的最小平均厚度分为4档,即10、15、20、25μm,与国际标准的规定等同。7.增加了对氧化膜封闭质量的控制,用磷铬酸浸蚀重量损失法测定时,损失应≤30mg/dm~2(仲裁法),酸浸重量损失法的应≤20mg/dm~2,导纳法的≤20μs。8.型材 “Aluminum profiles” GB5237-92 has been approved in the last year, compared with GB5237-85, the main technical contents are as follows: 1. Added LD30 alloy (6061). 2. Cross-sectional size tolerance to increase the ultra-high-precision (with DIN17615 equivalent). The standard clearly stipulates that the dimension deviation of the design mark must conform to the high-precision or ultra-high-precision level, and the unlabeled size must conform to the ordinary level. The revised section size deviation provisions and standards of countries in the world basic requirements. 3. Dimensions allow deviation, bending, twisting, etc., have increased the ultra-high-precision. 4.LD31 combined with the vertical depth of indentation to 0.05mm, but the provisions of the United States standards there is still a gap. 5. Increase the profile of ingot control, requiring profile ingot must be homogenized. 6. The oxide film minimum average thickness is divided into 4 files, that is, 10,15,20,25μm, equivalent to the provisions of international standards. 7. Increased the quality of the control of the oxide film, with phosphorus chromic acid etching weight loss method, the loss should be ≤ 30mg / dm ~ 2 (arbitration method), acid leaching weight loss method should be ≤ 20mg / dm ~ 2 Admittance method of ≤ 20μs. 8 profiles