Steel plate is the main material in the production of stainless steel pipe. It not only has sufficient strength, but also can withstand high pressure during operation. At the same time, it also has good technical performance to meet certain requirements for steel performance in construction

1) Have good mechanical properties. Mechanical properties include yield strength, tensile strength, impact toughness, elongation, bending angle and hardness. Tensile strength refers to the stress that the stainless steel pipe can bear when it breaks. It is generally represented by symbol a, and its unit is kg / mm.

The stainless steel pipe deforms after being subjected to external force. At first, the deformation is proportional to the external force. However, when the external force is applied to a certain extent, the deformation of the steel plate is not proportional to the force, and the deformation increases significantly. At this time, the force on the stainless steel pipe is the yield strength. The symbol shows that the unit is kg / mm.

When the stainless steel pipe is pulled and broken by tension, the ratio of its tensile length to the original length is called the tensile rate, which is expressed by the symbol B, and the unit is percentage. The resistance of stainless steel pipe to impact load is called impact toughness, which is represented by the symbol AK, and the unit is kilogram meter / centimeter. The ability of metal materials to resist hard objects pressing into the surface is called hardness. According to the measurement method, it can be divided into cloth hardness (HB), Rockwell hardness (HR), Vickers hardness (HV) and shore hardness (HS). Generally, steel with higher hardness has higher strength. The bending angle refers to the angle when the stainless steel pipe is subjected to the bending test on the tensile testing machine, and the angle when cracks occur is called the bending angle.

The above properties can be measured on the tensile testing machine and impact testing machine with the samples described in the appendix. 2) Good weldability is required.

3) It shall have good atmospheric corrosion resistance.

4) Low aging sensitivity is required. In aging sensitivity, aging impact value usually refers to the impact value sampled on the test piece after 10% tensile and 250 ℃ tempering for 1 hour. Generally, the C value of steel used for making stainless steel pipes shall not exceed 50%, otherwise, the tendency of brittle fracture will become greater.

At present, the steel plates used to make steel penstocks in China are mainly carbon steel and ordinary low alloy structural steel.