03
2019
-
12
Three-grade deformed steel bar, understand
Author:
Widely used in civil engineering such as houses, bridges, roads, especially railways!
Main purpose
Widely used in civil engineering such as houses, bridges, roads, especially railways!
Bending performance
The bending center diameter of the reverse bending test is increased by one deformed steel diameter compared with the bending test. First bend 45 degrees in the forward direction, then bend 23 degrees in the reverse direction, and then bend 23 degrees in the reverse direction. After the reverse bending test, there shall be no cracks on the surface of the bending part of the deformed steel bar.
surface quality
The surface of deformed steel bar shall be free of cracks, scabs and folds. Bumps are allowed on the surface of the deformed steel bar, but they shall not exceed the height of the transverse rib. The depth and height of other defects on the surface of the deformed steel bar shall not exceed the allowable deviation of the size of the location.
mechanical property
1. Yield point (physical yield strength): the stress obtained by dividing the maximum or minimum load by the original cross-sectional area is the yield point, the upper yield point and the lower yield point of the sample when the load does not increase or starts to decrease during the tensile process of the sample and the sample can still continue to deform.
2. Tensile strength (strength limit): When the specimen is stretched, the maximum load it bears before breaking divided by the stress obtained from the original cross-sectional area is called tensile strength, which represents the maximum resistance of the deformed steel to damage under the action of tension.
3. Elongation (elongation): the percentage of the increased length of the gauge length and the original gauge length of the sample after breaking, called elongation.
chemical composition
Carbon: increasing the carbon content of steel can improve the strength of steel, but make the welding performance and cold bending performance of steel worse.
Phosphorus: can significantly improve the strength limit of steel, but make the cold brittleness, weldability and cold bending property of steel worse.
Sulfur: Sulfur is harmful to most properties of steel. Oxygen: oxygen has adverse effects on most properties of steel.
Manganese: Manganese can significantly improve the strength limit of steel, but reduce the elongation of steel, and the content is too high, and the weldability becomes poor.
Silicon: silicon can improve the yield strength of steel, but when the content is too high, it will increase the cold brittleness of steel, and the welding performance will become poor.
Nitrogen: nitrogen will degrade most of the properties of steel.
The above are the mechanical properties of deformed steel bars and the influencing factors. Therefore, the chemical composition determines the mechanical properties of steel. Different steels use different chemical compositions, and the mechanical properties are also different, so there are various steel products.
Widely used in civil engineering such as houses, bridges, roads, especially railways!
Bending performance
The bending center diameter of the reverse bending test is increased by one deformed steel diameter compared with the bending test. First bend 45 degrees in the forward direction, then bend 23 degrees in the reverse direction, and then bend 23 degrees in the reverse direction. After the reverse bending test, there shall be no cracks on the surface of the bending part of the deformed steel bar.
surface quality
The surface of deformed steel bar shall be free of cracks, scabs and folds. Bumps are allowed on the surface of the deformed steel bar, but they shall not exceed the height of the transverse rib. The depth and height of other defects on the surface of the deformed steel bar shall not exceed the allowable deviation of the size of the location.
mechanical property
1. Yield point (physical yield strength): the stress obtained by dividing the maximum or minimum load by the original cross-sectional area is the yield point, the upper yield point and the lower yield point of the sample when the load does not increase or starts to decrease during the tensile process of the sample and the sample can still continue to deform.
2. Tensile strength (strength limit): When the specimen is stretched, the maximum load it bears before breaking divided by the stress obtained from the original cross-sectional area is called tensile strength, which represents the maximum resistance of the deformed steel to damage under the action of tension.
3. Elongation (elongation): the percentage of the increased length of the gauge length and the original gauge length of the sample after breaking, called elongation.
chemical composition
Carbon: increasing the carbon content of steel can improve the strength of steel, but make the welding performance and cold bending performance of steel worse.
Phosphorus: can significantly improve the strength limit of steel, but make the cold brittleness, weldability and cold bending property of steel worse.
Sulfur: Sulfur is harmful to most properties of steel. Oxygen: oxygen has adverse effects on most properties of steel.
Manganese: Manganese can significantly improve the strength limit of steel, but reduce the elongation of steel, and the content is too high, and the weldability becomes poor.
Silicon: silicon can improve the yield strength of steel, but when the content is too high, it will increase the cold brittleness of steel, and the welding performance will become poor.
Nitrogen: nitrogen will degrade most of the properties of steel.
The above are the mechanical properties of deformed steel bars and the influencing factors. Therefore, the chemical composition determines the mechanical properties of steel. Different steels use different chemical compositions, and the mechanical properties are also different, so there are various steel products.
