Is crack allowable for wear plate surface quality?

The production process of wear-resistant composite plate is made of metallurgical surfacing welding, the welding current is generally 350 500A, the temperature of the welding arc reaches 1000 1500, the instantaneous high temperature makes the welding wire and the mother plate reach the melting point to form a molten pool (the so-called welding bead), and the alloy powder added to the molten pool is melted to form a surfacing deposition layer. In the process of surfacing welding, the temperature of the motherboard adjacent to the molten pool will reach 600 800, or even higher, because the motherboard is generally made of ordinary Q235 low-carbon steel, and the wear-resistant layer is high carbon and high chromium, so in the surfacing process, the temperature difference of each part of the motherboard is very large, resulting in extremely uneven expansion, contraction and deformation, because the motherboard is firmly fastened around the pressing plate, can not be deformed freely, plus the wear-resistant layer is a welding wire made of a large number of alloy powder for metallurgical surfacing on the motherboard, forming a typical high hardness, high wear-resistant material, Because the thermal expansion coefficient of the surfacing layer and the motherboard is quite different, the motherboard with good toughness can withstand large thermal deformation, and the ability of the high-hardness surfacing layer to withstand thermal deformation is almost zero, so it produces great thermal stress inside, and if this stress is not released immediately, it is easy to break, crack, and wear resistant layer falling off in the process of later processing (such as curling). In the cooling process after thermal deformation, in order to release the welding stress existing in the surfacing composite steel plate, many cracks of different sizes will be generated on the surface of the surfacing layer perpendicular to the direction of the weld bead, and this crack is the result of stress release and does not affect the use.

These cracks look easy to worry about, for fear that the cracks of the wear-resistant composite steel plate will spread to the mother plate during use, or even fear of breaking or falling off, this kind of worry about cracks is unnecessary. The wear-resistant composite steel plate is produced by welding process, which belongs to metallurgical combination, and the bonding performance is very good. Cracks do not fall off or break during use.

If you are referring to the composite wear-resistant steel plate, there may be cracks on the surface, and the cracks on the surface layer of the wear-resistant layer will not affect the performance.

However, a single material of wear-resistant steel plate is not allowed to have cracks, bubbles and other defects, the general hot-rolled steel plate factory is strictly implemented by standards, and now the best hot-rolled wear-resistant steel plate BTW1 wear-resistant plate on the market will definitely not exist The surface quality is not up to standard.

I do wear-resistant surfacing welding, and it is very normal for you to have cracks on the surface. A crack is a stress-relieving crack that occurs during hardfacing. But cracks are irregular cracks.

The length of the crack cannot exceed 10mm. If you buy a composite wear plate, the acceptance criteria: 1. Surface hardness (HRC62-63).

2. Whether the thickness and size of the wear-resistant layer meet the requirements. 3. Surfacing quality (whether there is spalling, porosity, surfacing layer adhesion, flatness, etc.). 4. Wear-resistant layer metal composition, (manufacturers can be required to provide welding wire manufacturers, ingredients).

If you have any questions, then communicate and contact, forget !!

Hello, at present, the quality of bimetallic wear plates does not have the standard you said, and it is generally controlled in the factory. It is important to note the difference between steel plate and wear plate, which is not one thing.

The manufacturer fools you, there are cracks that contain a lot of impurities of boiling steel, 235 grade, you ask the manufacturer to 345 level of calm steel, steel model 345b or above.

The three major failure modes of wear plate materials are: wear, fracture, and corrosion. The failure modes of wear-resistant castings are the main failure modes such as wear, fracture and deformation.

1. Wear and tear failure.

Wear failure is the main mode of failure of all metal surfaces such as wear-resistant castings, especially in strong abrasive wear, where wear-resistant steel is gradually worn out and eventually fails. The hardness of wear-resistant steel is an important factor affecting its wear.

Generally speaking, the hardness of the wear-resistant parts is more than 1 times higher than the hardness of the material to obtain better wear resistance, which is the hardness of the working surface of the wear-resistant parts after wear rather than the initial hardness before wear. However, the higher the hardness, the better, because the higher the hardness, the more brittle and easy it is to break.

2. Failure of fracture.

If the wear-resistant parts are not properly installed, such as the back and the cylinder are not face-to-face but local contact when the liner is installed, it is easy to fracture. To improve the impact and toughness of wear-resistant parts, reducing their crack propagation rate will be conducive to fracture resistance. At present, the hardfacing wear-resistant material has replaced the wear-resistant casting products.

3. Deformation failure:

Deformation failure is the low yield strength of wear-resistant parts, so that serious macroscopic plastic deformation occurs due to external force during use, and the shape of the casting changes and fails. Failure is mostly seen in wear-resistant manganese steel parts with low yield strength, such as ball mill working conditions with large impact, and severe reverse bow deformation of manganese steel liners can pull bolts or displace between liners and fall off.

Understanding the causes of the failure of wear-resistant parts will be of guiding significance for selecting wear-resistant steel plates suitable for working conditions.

Wear-resistant plate bimetallic multi-layered wear-resistant steel plate is a plate product specially used for large-area wear conditions, which is a plate product made of ordinary low-carbon steel or low-alloy steel with good toughness and plasticity by surfacing welding method with a certain thickness of high hardness and excellent wear resistance.

Introduction: Bimetallic composite wear-resistant steel plate is composed of two parts: low-carbon steel plate and alloy wear-resistant layer, and the wear-resistant layer generally accounts for 1 3 1 2 of the total thickness. During operation, the matrix provides comprehensive properties such as strength, toughness and plasticity to resist external forces, and the wear-resistant layer provides wear-resistant properties that meet the requirements of specified working conditions.

There is a metallurgical bond between the wear-resistant steel plate alloy wear-resistant layer and the matrix. Through special equipment, the automatic welding process is adopted to evenly weld the high-hardness self-protection alloy welding wire on the substrate. The number of composite layers is one to two layers or even more layers, and uniform transverse cracks appear due to the different alloy shrinkage ratios in the composite process, which is a significant feature of wear-resistant steel plates.

The wear-resistant layer is mainly chromium alloy, and other alloy components such as manganese, molybdenum, niobium, nickel and other alloys are also added. The microhardness of carbide can reach more than HV1700-2000, and the surface hardness can reach HRC58-62. The alloy carbide has strong stability at high temperatures, maintains high hardness, and also has good oxidation resistance, and can be used completely normally within 500.

Wear-resistant steel plate has high wear resistance and good impact performance, can be cut, bending, welding, etc., can be welded, plug welded, bolted and other ways to connect with other structures, in the process of maintenance site has the characteristics of time-saving, convenient, etc., widely used in metallurgy, coal, cement, electric power, glass, mining, building materials, bricks and tiles and other industries, compared with other materials, has a high cost performance, has been favored by more and more industries and manufacturers.

Wear-resistant steel plate crack refers to the fact that there will be many cracks on the surface of the wear-resistant composite steel plate, which is a unique feature of wear-resistant composite steel plate, and other wear-resistant steel plates do not have. The crack occurs because the wear-resistant composite steel plate is produced by welding method, and the wear-resistant composite steel plate will produce a large amount of welding stress due to high temperature (about 3000-5000 degrees) in the welding production process. Welding stress is a harmful thing, if not eliminated in time, it is easy to break, crack and other problems in later use.

Cracks on the surface of wear-resistant composite steel plates are the result of welding stress relief. In other words, because of the formation of cracks, the wear-resistant composite steel plate releases the welding stress during the production process. In this way, the wear-resistant composite steel plate will not be deformed, broken and other problems.

These cracks look easy to worry about, fearing that the cracks will expand or even break or fall off during the use of wear-resistant composite steel plates. This worry about cracks is superfluous, and the wear-resistant composite steel plate is produced by welding process, which belongs to metallurgical bonding, and the bonding performance is very good. Cracks do not fall off or break during use.