1. Surface inconsistency: only pickling and passivation are carried out on the weld, which also causes uneven surface and affects the appearance.

2. Uneven polishing and passivation: pickling and passivation treatment after manual polishing is difficult to achieve uniform treatment effect for workpieces with large area, and the ideal uniform surface cannot be obtained. And the labor cost, auxiliary material cost is also higher.

3. Weld defects: the weld defects are serious, which can be made up by manual mechanical polishing, resulting in uneven surface and poor appearance.

Scratch is difficult to remove: the whole pickling passivation can not remove all kinds of scratches produced in the processing process, and can not remove impurities such as carbon steel and spatter adhering to the surface of stainless steel due to scratch and welding spatter, resulting in chemical corrosion or electrochemical corrosion and rust in the presence of corrosive medium.

5. The scratch caused by human factors is more serious: in the process of hoisting, transportation and structural processing, the scratch caused by bumping, dragging, hammering and other factors is more serious, which makes the surface treatment more difficult, and it is also the main cause of corrosion after treatment.

6. Limited pickling capacity: pickling passivation paste is not omnipotent, and it is difficult to remove black oxide scale produced by plasma cutting and flame cutting.

7 equipment factors: in the process of bending and bending of profiles and plates, the scratch and crease are also the main causes of corrosion after treatment.

Other factors: stainless steel raw materials in the procurement, storage process, due to the hoisting, transportation process of collision and scratch is also more serious, is also one of the causes of corrosion.