The black industrial chain of waste steel bars was exposed. As consumers, how can we better distinguish whether steel bars are qualified or not? Judge a book by its cover. Whether the reinforcement is straight and undamaged, and whether there are cracks, oil stains, granular or flaky old rust on the surface. The depth of corrosion, pitting and damage on the surface of steel bar should not be greater than 1/2 of the maximum negative deviation value of steel bar thickness. Check the fracture for interlayer and delamination defects.

The surface luster of high-quality steel bars is consistent, and the color is dark blue and gray, while the surface of inferior steel bars is gray, and the iron pieces will fall off or even appear dark red after being wiped or knocked.

Generally, hot-rolled ribbed steel bars will carry information such as manufacturer code, steel bar brand and diameter.

The surface of steel bars produced in small factories is rough, the transverse ribs of ribbed steel bars are large and irregular, the cross section is not round, and the second is irregular ellipse. Inferior steel bars are mostly products of indefinite size, and there are many cracks, burrs and other defects at the end. This kind of steel bar must not be bought and used!

If the appearance inspection is qualified, we also need to check the actual size of the steel bar. Steel tape should be used to measure the length, and micrometer and vernier caliper should be used to measure the thickness of both sides.

1, check the actual size of the hot-rolled steel bar, and measure the inner diameter of the ribbed steel bar accurately to 0.1mm.

2. When measuring the rib height of ribbed steel bars, it is necessary to measure the average rib height on both sides of the same section, that is, measure the maximum outer diameter of steel bars minus the inner diameter, and half of the obtained data is the rib height, accurate to 0.1mm.

3. The average rib spacing is also used to check the transverse rib spacing of ribbed steel bars. Measure the distance between the center ofNo. 1 and the center ofNo.1on one side of the steel bar, and divide the obtained data by 10, which is the spacing of transverse ribs, and the accuracy is 0.1mm. Therefore, when you buy steel bars, you must buy products produced by regular national steel mills, not non-standard steel bars produced by small factories. When purchasing, ask the point of sale to provide the quality certificate and test report of the steel bar. In addition, a 20-year-old steel bar industry provides a method for inspecting steel bars: cutting steel bars with a length of 1 meter, weighing and measuring the diameter with an electronic scale. Diameter? 0.006 17 is the weight per meter (unit kilogram), and there is a diameter figure on the steel bar.