45号钢φ5×1无缝钢管,用以制造凿岩机水针。对它的几何尺寸精度要求较高,其外表面光洁度必须保证在▽4以上,还要保证具有较高的抗拉强度及塑性。在加工工艺性上,要求其在冷轧水针锥形口和热挤头部时,均要保证不产生裂纹。在国外,西德曼尼斯曼钢管厂将这类钢管列为精密无缝钢管生产,一般均采用光亮退火状态供货。在国内,由于此类无缝钢管生产周期长、成本高、利润低,各钢管厂大多不乐意生产,因而形成空缺,不得不依靠进口。江苏省常熟钢管厂为填补国內空缺,调整产品结构,努力生产国家所需短线产品。自1980年 45 steel φ5 × 1 seamless steel pipe, used to manufacture rock drill water needle. Its geometric precision requirements are high, the outer surface finish must be guaranteed at ▽ 4 above, but also to ensure high tensile strength and plasticity. In terms of processability, it is required to ensure that cracks are not generated when the tapered needle of the cold-rolled water needle and the hot extrusion head are required. Abroad, West Germany Manni Siman steel pipe plant will be classified as precision seamless steel pipe production, are generally used bright annealing state of the supply. In China, due to the long production cycle, high cost and low profit of such seamless steel pipe, most of the steel pipe mills are not willing to produce, thus creating a vacancy and having to rely on imports. Changshu Steel Plant in Jiangsu Province to fill the domestic vacancies, adjust the product mix, and strive to produce the required short-term products. Since 1980