Testing methods for metallic materials

The standards used in China's metallurgical products are national standards (code name "GB"), ministerial standards (Ministry of Metallurgical Industry standard "yb", Ministry of Machinery Industry standard "jb", etc.), and enterprise standards at level three.

1、 Packaging inspection

According to the type, shape, size, accuracy, and corrosion resistance of metal materials.

1. Loose: refers to unpackaged, polished ingots, blocks (not afraid of corrosion and not expensive), large steel (large steel, thick steel plates, rails), pig iron, etc.

2. Bundling: Refers to smaller sizes with little impact of corrosion on usage, such as small and medium-sized steel, pipe steel, wire, thin plate, etc.

3. Box (barrel): Refers to corrosion-resistant, small, and thin products, such as tinplate, silicon steel sheets, magnesium ingots, etc.

4. Shaping: refers to wires, steel wire ropes, steel strands, etc.

For bundled boxes and shaft packaging products, the first step is to check if the packaging is complete.

2、 Mark inspection

A logo is a symbol that distinguishes the material and specifications of materials, mainly indicating the supplier's name, brand number, inspection batch number, specifications, size, level, net weight, etc. The logo has;

1. Color coating: Apply various colors of paint on the end faces and ends of metal materials, mainly used for steel, pig iron, colored raw materials, etc.

2. Printing: The method of stamping or painting on the designated parts (end face, end) of metal materials, explaining the material's grade, specifications, standard number, etc. Mainly used for medium and thick plates, profiles, non-ferrous materials, etc.

3. Tagging: Metal materials such as bundles, boxes, and shafts are labeled outside to indicate their brand, size, weight, standard number, supplier, etc.

The marking inspection of metal materials should be carefully identified and properly protected during transportation, storage, and other processes.

3、 Inspection of specifications and dimensions

Specification size refers to the nominal size of the main parts (length, width, thickness, diameter, etc.) of a metal material.

1. Nominal size: It is the ideal size that people want to obtain in production, but it has a certain difference from the actual size.

2. Size deviation: The difference between the actual size and the nominal size is called size deviation. A deviation greater than the nominal size is called a positive deviation, and a deviation less than the nominal size is called a negative deviation. Within the specified range of the standard, it is called allowable deviation. If it exceeds the range, it is called size deviation. Deviation is considered unqualified product.

3. Accuracy level: The allowable size deviation of metal materials is specified in several ranges, and is divided into several levels according to the different allowable size deviation, which is called accuracy level. The accuracy level is divided into ordinary, higher, advanced, etc.

4. Delivery length (width): refers to the main dimensions of metal material delivery, which refers to the length (width) specification that the metal material should have at the time of delivery.

5. Normal length (indefinite length): There is no specific regulation on the length, but it must be within a specified length range (depending on the variety and length, determined by the department or factory).