How many grades are there for hot rolled steel bars? What are the characteristics and uses of steel

Graded by intensity.

Hot-rolled steel bars are graded according to the standard value of yield strength and are divided into four grades:

The standard yield strength of the steel bar is 235MPa, the diameter is 8 20mm, and the elastic modulus is 210GPA. (Cancelled).

The standard yield strength of the steel bar is 335MPa, the diameter is 6 50mm, and the elastic modulus is 200GPA.

The standard yield strength of the steel bar is 400MPa, the diameter is 6 50mm, and the elastic modulus is 200GPA.

The standard value of the yield strength of the steel bar is the same as that of the HRB400 steel bar, which is also 400MPa, the diameter is 8 40mm, and the elastic modulus is 200GPA.

Hot-rolled steel bar is a finished steel bar formed by hot rolling and naturally cooled, which is pressed by low-yard crude carbon steel and ordinary alloy steel at high temperature, mainly used for the reinforcement of reinforced concrete and prestressed concrete structures, and is one of the largest steel varieties used in civil engineering and construction projects. Laughing.

It is distinguished according to the standard value of the yield strength of the reinforcement.

Hot-rolled round HPB300 - yield strength 300MPa

Hot-rolled ribbed HRB335, HRBF335 - yield strength 335MPa

HRB400, HRBF400, RRB400 – yield strength 400MPa

HRB500, HRBF500 - yield strength 500MPa

Hot-rolled steel bar is a finished steel bar formed by hot rolling and naturally cooled, which is pressed by low carbon steel and ordinary alloy steel at high temperature, mainly used for reinforcement of reinforced concrete and prestressed concrete bridge soil structure, and is one of the most widely used steel varieties in civil engineering and construction projects.

Hot-rolled steel bars are steel bars with a diameter of millimeters, most of which are rolled into wire rods; A diameter of 10 to 40 mm is generally a straight strip 6 to 12 meters long. The hot-rolled steel bar should have a certain strength limb, that is, the yield point and tensile strength, which is the main basis for structural design. It is divided into two types: hot-rolled round steel bar and hot-rolled ribbed steel bar.

The hot-rolled steel bar is soft and rigid, and when it is broken, it will produce necking and large elongation.

Answer]: Hot-rolled steel bars can be divided into four grades according to their mechanical properties.

The grade steel bar is a smooth round steel bar rolled from Q235 carbon structural steel. Its strength is low, but it has good plasticity, toughness and cold working performance, and is widely used in the main stressed steel bars, structural bars and stirrups of ordinary reinforced concrete.

Grade and grade steel bars are ribbed steel bars rolled from low-alloy calmed beam steel and semi-calmed steel. It has high strength, good plasticity and weldability of wild slag mountain, strong adhesion with concrete, and is widely used in large and medium-sized reinforced concrete structures. After cold drawing, it can be used as a prestressed steel bar.

Grade steel bars are ribbed steel bars rolled from medium carbon low-alloy steel. It has high strength and ensures plasticity and toughness while improving strength. The weldability is poor, and it is mainly used as a prestressed steel bar.

If welding is required, appropriate welding methods and post-welding heat treatment processes should be used to ensure that the welded joint and its heat-affected zone do not produce hardened structure and do not cause brittle fracture.

According to the performance of the rebar, there are four grades. 1. According to mechanical propertiesgrade reinforcement. 300 420 class); Level.

reinforcement (335 455 grades); Grade bars (400 540) and grade bars (500 630).

2. According to the size of the diameterSteel wire (diameter 3 5mm), thin steel bar (diameter 6 10mm), thick steel bar (diameter greater than 22mm).

3. According to the production processHot-rolled, cold-rolled, cold-drawn steel bars, as well as heat-treated steel bars made by heat treatment of grade steel bars, the strength is higher than the former.

Formula for calculating the load bearing of rebar.

Flat bars. Steel plate, steel strip w = width and thickness.

Square steel. w=Bian called to be Mu Hu Hechang

Bar. Wire rod, steel wire w = diameter

Steel pipe w = wall thickness (outer diameter - inner diameter).

Equilateral angle steel w = side thickness (2 side width - side thickness).

Unequal angle steel w = side thickness (long side width + short side and forest width - side thickness) I-beam. w = waist thickness [height + f (leg width - waist thickness)].

Channel steel w = waist thickness [height + e (leg width - waist thickness)].