Wie man gefälschten und minderwertigen Stahl vom Aussehen unterscheidet

1 Fake and inferior steel materials are prone to folding. Folding is a variety of fold lines formed on the surface of the steel, and such defects often penetrate the longitudinal direction of the entire product. The reason for the folding is that the counterfeit manufacturers are pursuing high efficiency, and the amount of reduction is too large, resulting in ears. The folding will occur during the next rolling. The folded product will crack after bending, and the strength of the steel will be greatly reduced.

2 The appearance of counterfeit and inferior steel is often pitted. The pitted surface is caused by the serious wear of the rolling groove, which causes irregular irregularities on the surface of the steel. As the counterfeit and inferior steel manufacturers are pursuing profits, the groove rolling often exceeds the standard.

3 The surface of counterfeit and inferior steel is prone to scars. There are two reasons:

(1) Inferior and counterfeit steel materials are uneven and have many impurities.
(2) The guide and guard equipment of the counterfeit and inferior steel manufacturers are simple and easy to stick to the steel. These impurities will easily cause scars after biting the roll.

4 The surface of the fake and inferior material is prone to cracks, because its billet is adobe, and the adobe has many pores. The adobe is subjected to thermal stress during the cooling process, causing cracks, and there will be cracks after rolling.

5 Counterfeit and inferior steel materials are easy to scratch because of the simple equipment of manufacturers of fake and inferior materials, which can easily produce burrs and scratch the surface of the steel. Deep scratches reduce the strength of steel.

6 The fake and inferior steel has no metallic luster and is light red or pig-iron-like color. There are two reasons: (1) Its blank is adobe. (2) The rolling temperature of counterfeit and inferior steel is not standard, and their steel temperature is visually inspected. In this way, rolling cannot be carried out in the specified austenite area, and the performance of the steel will naturally not meet the standard.

7 The cross ribs of counterfeit and inferior steel are thin and low, and often dissatisfied. The reason is that in order to achieve a large negative tolerance, the reduction of the first few passes of the finished product is too large, the iron-type is too small, and the hole type is not full.

8 The cross-section of the counterfeit and inferior steel is elliptical. The reason is that in order to save material, the reduction of the first two passes of the finished roll is too large. The strength of this kind of rebar is greatly reduced, and it does not meet the standard of the shape of the rebar.

9 The composition of the high-quality steel is uniform, the tonnage of the cold shear is high, and the end face of the cutting head is smooth and tidy. However, due to the poor material, the end face of the cutting head often has meat loss, that is, it is uneven and has no metallic luster. Moreover, because the products of the fake and inferior material manufacturers have few cuts, big ears will appear at the beginning and the end.

10 The fake and inferior steel material contains many impurities, the density of the steel is small, and the size is too large. Therefore, it can be weighed and checked without a vernier caliper. For example, for rebar 20, the national standard stipulates that the maximum negative tolerance is 5%. When the length is 9M, its single theoretical weight is 120 kg. Its minimum weight should be: 120 X(l-5%)=114 kg, The actual weight of a single piece weighed out is less than 114 kg, it is fake and inferior steel because its negative tolerance exceeds 5%. Generally speaking, the effect of phasing weighing will be better, mainly considering the problem of cumulative error and probability theory.

11 The inner diameter of fake and inferior steel fluctuates greatly because of:

(1) The steel temperature is unstable and has a yin and yang side.
(2) The composition of steel is not uniform.
(3) Due to the simple equipment and low foundation strength, the rolling mill bounces greatly. There will be a large change in the inner diameter of the same week so that the uneven force of the steel bar is prone to fracture.

12 The trademarks and printing of high-quality materials are relatively standardized.

13 For large threads with a steel diameter of 16 or more, the distance between the two trademarks is above IM.

14 The longitudinal ribs of counterfeit and inferior steel rebar are often wavy.

15 As the counterfeit steel manufacturers do not drive, they are loosely packed. The side is oval.

16 Rebar and wire rod packing general rebar 1.5t/piece, wire rod 1.3t/piece.

17 The steel plate produced by inferior steel mills has obvious waves on the surface due to poor rolling and cooling technology.

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