精密管质检合格

添加钛、铌等微合金元素形成弥散的氮化物或碳氮化物，导致冷轧精密光亮钢管的韧脆转变温度升高。(3)晶粒尺寸对韧脆转变温度有影响，随着晶粒粗化，韧脆转变温度升高。冷轧和精密光亮钢管的晶粒脆化倾向得到了广泛的应用。高春铁（0.01% C）的Tc在该温度以下的100C完全易碎。冷轧精密光亮钢管中大部分合金元素都提高了韧脆转变温度和冷脆倾向。室温以上发生韧性断裂时，冷轧精密光亮钢管的断口为韧窝断裂，低温脆性断裂时断口为解理断裂。

Following the decline in crude steel production in the first ten days of this month, crude steel production rose again in the first ten days of this month. Inventories of heat preservation and anticorrosion pipe manufacturers and factories also declined. The production situation of secondary or steel plants is not clear. At present, as raw material prices continue to fall, consumer enterprises still have profit margins; coupled with financial pressure, most steel mills need to maintain operation in order to continue to obtain savings; therefore, steel mills still adhere to a higher start-up rate; Anshan region, for example, as of this month, Tangshan blast high production capacity application rate. Up to.0%, the rate of increase was normal.