What is the S690QL1 specification as rolled delivery state

S690QL1 specification annealing is to heat the steel to 30 ~ 50℃ above the critical temperature, keep it in the heat treatment furnace for a period of time, and then cool it down to room temperature with the furnace. The purpose of S690QL1 specification annealing is to refine the grain of steel, eliminate internal stress and reduce hardness, improve cutting performance, increase toughness and plasticity, and facilitate welding and rolling processes. S690QL1 specification annealing can be complete annealing, incomplete annealing, stress relief annealing, isothermal annealing and spheroidizing annealing.

The toughness of steel such as S690QL1 specification is the ability of steel to absorb energy in the process of plastic deformation and fracture, and also the ability of steel to resist impact load. It is related to and different from the plasticity of steel. It is the comprehensive performance of strength and plasticity. The strength plasticity index of steel is obtained by static tensile test. When these indexes are used to bear the dynamic load structure, there are obvious limitations.

Bridge steel plates are thick steel plates made of carbon steel and low-alloy steel for bridge construction. The main applications of bridge steel plates are to build railway bridges, highway bridges, and sea-crossing bridges. The bridge steel plates are required to have high strength, durability and bear the load and impact of rolling stock. Bridge steel plates have good water resistance, low thermal conductivity, flat and lubricated surface. The main grades of bridge steel plates are A709 grade 50, A588 grade B, S690QL1 specification and so on.

India began to implement the national blockade measures on March 25. After two extensions, the national blockade measures have been implemented for nearly 50 days, which has a huge impact on the S690QL1 specification economy. To that end, modi said in a televised speech on the evening of the 12th that India will launch a total of 20 trillion Indian rupees one point eight eight Trillion yuan).

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