EnglishViews: 0 Author: Site Editor Publish Time: 2025-12-01 Origin: Site
Mn22Cr2 cast in alloy liner is a high-performance wear-resistant component developed for high impact and strong wear conditions (such as initial breakage of large gyratory crushers and jaw crushers). The core lies in the metallurgical combination of high hardness alloy blocks (inlays) and high toughness Mn22Cr2 high manganese steel matrix (matrix) through the casting process, achieving the optimal combination of impact resistance and wear resistance. The following will systematically explain the key links in raw material processing and production technology.
1、 Raw material selection and pretreatment
1. Mother material (Mn22Cr2 high manganese steel)
Ingredient control: Strictly follow the standards, with a focus on controlling C, Mn, and Cr elements. Carbon content (~1.20%) ensures work hardening ability, manganese content (~22%) ensures austenite stability and toughness, and chromium content (~2.0%) refines grains and improves initial hardness and corrosion resistance. It is necessary to strictly control harmful elements such as S and P (usually requiring P ≤ 0.04% and S ≤ 0.025%).
Furnace charge processing: High quality scrap steel, manganese iron, chromium iron, etc. are used. Clean and dry before entering the furnace to prevent gas inclusions. Scrap steel should be free from severe rust and oil stains.
2. Inlay material (high hardness alloy block)
Material selection: High chromium cast iron (such as Cr20~28%), tungsten titanium alloy or special hard alloy are usually used. Its macroscopic hardness (HRC ≥ 58) needs to be significantly higher than that of the parent material to form an effective wear-resistant point.
Pre treatment: Process the alloy into the designed shape (such as cylinder, square bar), and perform sandblasting or acid washing treatment to thoroughly remove oxide scale and oil stains, ensuring a clean surface. Subsequently, preheating (usually 300-400 ° C) is carried out to remove moisture and reduce thermal shock when in contact with the molten steel.
3. Casting auxiliary materials
Molding materials: Water glass sand, resin sand, or chromite sand are used to ensure the strength and surface quality of the mold.
Coating: Use alcohol based zircon powder coating with high fire resistance to prevent sand sticking.
2、 Core production process flow
1. Mold design and inlay pre setting
According to the wear pattern of the lining plate (such as the bottom of the jaw plate, the impact zone of the cone breaking and rolling groove wall), a cavity is set at a specific position of the mold (wooden or metal mold) to accurately fix the preheated inlay. The fixation must be firm to prevent displacement during pouring.
2. Melting and pouring
Smelting: carried out in an electric arc furnace or medium frequency induction furnace. Adopting high-temperature melting (~1550 ° C), slag making dephosphorization and desulfurization, and pre deoxidation processes. Perform final deoxidation and alloy fine-tuning before steelmaking.
Pouring: The key lies in temperature and speed control. The temperature at which the molten steel is discharged from the furnace should be slightly higher than that of ordinary high manganese steel (about 1520-1550 ° C) to ensure good fluidity and achieve sufficient fusion between the molten steel and the inlay. Pouring should be fast and smooth to avoid turbulent flow scouring the inlay.
3. Inlay casting composite process
Inject high-temperature molten steel into the mold cavity and wrap the pre embedded body. The interface between the two undergoes element diffusion and micro metallurgical bonding, forming a strong transition layer. This is the core of the success or failure of the process, which depends on the precise coordination of the cleanliness of the inlay, preheating temperature, and superheat of the steel liquid mentioned above.
4. Solidification, cleaning, and heat treatment
Solidification control: Reasonably set up risers and cold iron to achieve sequential solidification, ensuring that there are no casting defects such as shrinkage holes and porosity in the embedded area.
Sand cleaning and cutting: After sanding, remove the sprue and perform shot blasting cleaning.
Heat treatment (water toughening treatment):
Heating up: Slowly heat to~1050-1100 ° C to fully dissolve the carbides in the austenite.
Insulation: Determine the time (usually 2-4 hours) based on the thickness of the lining plate section to ensure uniformity of austenite.
Quenching: Quickly immerse in water (water temperature ≤ 40 ° C) for rapid cooling to obtain a single and strong austenite structure, avoiding the precipitation of carbides along grain boundaries.
Follow up: Tempering is generally not carried out.
3、 Key points of process quality control
Combined with interface detection: Through ultrasonic testing (UT) or macroscopic corrosion inspection, ensure that the interface is free of slag inclusion, porosity, and non fusion defects.
Hardness and metallographic verification:
Matrix: After processing, the Brinell hardness (HB) remains between 200-250, and the microstructure is a single austenite.
Embedded body: Hardness HRC ≥ 58, metallographic composition of eutectic carbide+martensite/austenite.
Transition zone: It should present a gentle hardness gradient and a good organizational transition.
Dimensional accuracy: After machining, the key installation dimensions must comply with the drawing tolerances to ensure perfect assembly with the host.
4、 Advantages and Application Conclusions
The Mn22Cr2 embedded casting liner plate has achieved the design concept of "tough matrix to withstand impact, hard embedded to resist wear" through scientific material combination and rigorous process. Its lifespan can usually be increased by 30% -80% compared to traditional high manganese steel lining plates, especially suitable for crushing key impact wear areas of high hardness and large block materials.
