Core tip: for steel pipe, which is mainly used for stress corrosion, it is required to have solid solution and pickling state to avoid the mill. When the surface of the steel pipe is distributed with small cracks, folding and other defects need to be polished, the steel pipe after the grinding need to re - solid solution and pickling treatment to re - delivery. The tangential stress in the residual stress generated by the grinding is the principal stress of the SCC failure.

1、双相不锈钢的屈服强度比奥氏体不锈钢高一倍，应采用比后者小的变形量，冷轧时必须选用适当的车速及送进量，尽量减小纵向壁厚不均及轧折。冷拔时钢管减面率不宜过大。

1, the yield strength of duplex stainless steel is twice higher than that of austenitic stainless steel, which should be smaller than the latter, the speed and feed amount must be chosen in the cold rolling. Cold drawn steel tube reduction rate should not be too large.

2、钢管中间软化和成品热处理采用连续辊底式加热炉（出口处配水帘冷却装置），禁止采用电接触加热，后者不容易控制温度，升温速度很快，容易超温，使铁素体相数量超标，尤其在轧制薄壁管时，一旦控制不好，容易产生竹节状壁厚不均，尽管这种壁厚不均值不大（一般不超过0.1mm）。在电接触加热时，壁薄部位迅速升温，造成局部超温，使铁素体数量大大增加，甚至出现单相粗晶铁素体组织，降低了耐腐蚀性，随后酸洗时，这部位会产生局部过酸洗，使钢管报废。

2, intermediate and finished steel softening heat treatment using continuous roller hearth type heating furnace (water cooling device with exit), prohibited the use of electric contact heating, which is not easy to control the temperature and the heating rate is very fast, easy temperature, ferrite phase number exceed the standard, especially in the rolling of thin walled tube, not once good control, easy to produce bamboo like uneven wall thickness, while the wall thickness is not mean little (less than 0.1mm). In electric contact heating, thin wall parts rapid warming, cause local overheating, the amount of ferrite increases greatly, and even the emergence of single-phase coarse grain ferrite, reduced corrosion resistance, then pickling, this part will produce local pickling, make steel scrap.

3、成品管的固溶处理十分关键，不仅要消除成品管冷加工的残余应力，还要保证合适的两相比例以及成品管的表面质量。热处理时需要注意料温的均匀性和足够的保温时间，避免因固溶不充分使钢管表面残余应力过高，导致在某些介质中引发应力腐蚀。

3, the solid solution treatment is very important, not only to eliminate the residual stress of the finished pipe cold processing, but also to ensure the proper proportion of the two phases as well as the surface quality of the finished product. Heat treatment need to pay attention to the uniformity of the material temperature and enough time to avoid the solid solution does not fully make the surface of the steel pipe residual stress is too high, resulting in some of the media lead to stress corrosion.

4、对于主要用作耐应力腐蚀的钢管，需要固溶酸洗态交货，避免研磨态交货。当钢管表面分布有小裂纹、折叠等缺陷需要整管研磨时，研磨后的钢管需经重新固溶酸洗处理后再交货。因为研磨产生的残余应力中的切向应力是产生SCC破坏的主应力。

4, for the main resistance to stress corrosion of the steel pipe, the need for solid solution pickling state delivery, to avoid the grinding state of delivery. When the surface of the steel pipe is distributed with small cracks, folding and other defects need to be polished, the steel pipe after the grinding need to re - solid solution and pickling treatment to re - delivery. The tangential stress in the residual stress generated by the grinding is the principal stress of the SCC failure.