Localization development of cone crusher liners of HP5 cone crusher

METSO HP5 cone crusher is foreign imported equipment introduced by HAIKUANG company in 2010. Its features are as follows:

1. Large crushing ratio, short crushing process, saving material space and high productivity
2. The function of changing from coarse cavity to superfine cavity is only to change the cone crusher plates and rotate speed
3. By changing the cone crusher plates and adjusting the rotating speed, it can adapt to the transformation from medium crushing to artificial sand making or ultra-fine crushing. 

However, the fixed and moving cone liners are vulnerable parts, with large annual loss and high price, the supply cycle is long, which affects the normal production. Our foundry has many years of experience in making crusher liners, so it is decided to make the liners of the equipment domestically by us.

Selection of cone crusher liner material and analysis of the chemical composition

Crusher liner is an important part of the cone crusher, and also the main wear part. Its mechanical properties and service life are directly related to the working efficiency of crusher equipment. Service life and production cost become one of the most concerned technical and economic indicators for each user.

The cone crusher liner of crusher works under the working condition of medium and low impact force. The material requirements have a certain hardness, strength, good wear resistance and impact toughness. The strength and toughness of the lining plate mainly depend on the internal structure, and the cooling products of each steel after austenitizing are closely related to the hardenability of the steel, Therefore, the chemical composition of cone crusher liner is an important factor affecting its hardenability. The original crusher is made of ZGMn18Cr2Mo. The material contains high Mn and Mo. the manufacturing cost is high. If the crusher is made domestically according to its composition, the production cost is high and there is no competitive advantage. 

Based on the analysis of the factors affecting the strength, toughness and wear resistance of the wear-resistant steel, the wear-resistant high manganese steel (zgmn13cr2vtire) was developed with Mn, Si, Cr as the main elements and V, B, Ti, re as the trace elements, the details as following:

• C,1.05-1.25
• Mn, 12-14
• Si, 0.3-0.8
• Cr, 2-3
• V,0.2-0.4
• Ti, Re

"C" element

High manganese steel is a kind of steel with high carbon content. According to the structure and service conditions of high manganese steel castings, the carbon content changes in the range of 0.9-1.3%. For high manganese steel workpieces in service under strong extrusion and impact load, it is expected to reduce the C content appropriately and generally choose about 1.05-1.25%. In this way, single-phase austenite structure can be obtained after solution treatment, It has good plastic toughness, easy to produce work hardening in the process of external force deformation, and improves the wear resistance of the workpiece.

"Mn" element

Mn is the main alloy element in high-speed steel. Manganese plays an important role in enlarging the R-phase region and stabilizing austenite structure. In high manganese steel, the content is usually 10-14%. Because the workpiece is in service under high stress and has a large wall thickness, in order to obtain high toughness and prevent fracture during use, the content is about 12-14%.

The selection of manganese content mainly depends on the carbon content and the service conditions of the casting and makes manganese and carbon in an appropriate proportion to ensure the austenite structure. The manganese carbon ratio (Mn / C) is generally controlled at 9-11.

"Chromium" element

Chromium: it is one of the main alloy elements in wear-resistant steel. In high manganese steel, it can strengthen austenite greatly after solid solution in austenite, improve the work-hardening property of high manganese steel, and increase the wear resistance of high manganese steel. With the increase of chromium content, alloy carbides are formed with carbon and iron in steel, which can partially dissolve in solid solution to strengthen the matrix, improve the strength and hardness without reducing the toughness, improve the hardenability of steel, and reasonably match with manganese and silicon, which can greatly improve the hardenability.

"Si" element

Silicon: Silicon is 0.3-0.8% in high manganese steel. Its main function in steel is to deoxidize, improve the hardness and strength of the solid solution in steel, and play a strong role in improving the cold work deformation hardening rate in steel, so it can improve the wear resistance of steel. However, when the silicon content of high manganese steel is high, it is easy to produce grain boundary carbide, which will lead to cracking during casting and decarburization during heating and heat preservation.

"V, Ti" element

V, Ti is a strong carbide forming element with a high melting point and stable property. It usually exists in small particles, which can refine grains and improve many properties of high manganese steel. Moreover, due to the high hardness of VC and tic, it can play the role of high hard point wear-resistant phase, which can significantly improve the abrasive wear resistance of high manganese steel under high impact load.

"S" element

Sulfur: sulfur mainly exists in the form of sulfide. Segregation in steel seriously deteriorates the quality of steel and increases the cracking tendency of castings in the process of casting and heat treatment, so it should be less than 0.05%

"P" element

The solubility of phosphorus in high manganese steel is very low. When the content of phosphorus in steel is high, soluble eutectic phosphates will precipitate along the grain boundary. It can improve the plasticity, toughness and wear resistance of manganese steel, so as to increase the service life. Therefore, P content should be less than 0.06%

"Re" element

Rare earth is a kind of surface-active element, which concentrates on the liquid-solid interface during the crystallization process, hinders the diffusion of atoms, hinders the grain growth, refines the grain, and promotes the axial and wear resistance of steel.

Lost Foam Molding Process

HP5 Cone Crusher Mantle and Concave 

• Material: ZGMn13Cr2VTIRE
• Weight:  Mantle, 1930kg; Concave, 2400kg
• Thickest: 210mm
• Thinnest: 30mm
• The casting must not have any macro casting defects.

HP5 Cone Crusher Concave And Mantle

Preparation of foam pattern

The foam plastic is selected from our factory's self-made sheet with a density of 18-20g / cm3. It is made by hand: electric wire cutting and molding. Lost foam casting. Because it adopts dry sand without binder, the mold has good concession, so the casting line shrinks The rate is larger than that of clay sand casting. According to the structure, wall thickness and size of the casting, the linear shrinkage of the pattern is selected to be 3-3.5%. The cutting process of the appearance is as follows:

Design template-prepare foam sheet-cut foam pattern according to template-pattern bonding-sanding trimming-check dimensions.

HP5 Cone Crusher Liners Foam Pattern

Design of casting system and auxiliary system

Compared with the traditional clay sand casting, the lost foam casting system has more factors to control and has a greater impact on product quality. When designing the process, the principle of arranging the pouring position of the pouring system is as follows: Stable filling, avoid excessive fluctuations and rolling of the metal liquid in the cavity, and wrap the unvaporized liquid or solid foam inside the metal liquid, resulting in the formation of pores and slag inclusion defects in the casting.

Coating and drying

The coating is very important for the disappearance of negative pressure casting. It is the "barrier" between the liquid metal and the dry sand. It has three functions: 

• one is to prevent the casting from sticking to the sand, reduce the amount of the workpiece to be cleaned, and improve the surface finish of the casting; 
• The overall strength of the foam pattern can prevent the pattern from deforming or reinforcing the surface strength of the sand mold in real time when it is moved or buried in the sand, and reduce the sand rushing phenomenon during pouring. 
• The third is that the product of gasification and decomposition of the pattern can be affected by the negative pressure field.

Drain the mold in time to avoid air holes in the prayer pieces. This cage surface is based on magnesia powder as refractory aggregate, Guilin No. 5 as binder and water as the carrier. The coating has low cost, good coating performance, high coating strength, good toughness, no cracking, and the coating is automatically peeled from the casting after pouring. For HP5 crusher fixed and moving cone liner castings, the coating thickness is required to be 1.5-2mm and baked in hot air at 40-50 ℃ for 3-8 hours.

Boxing

A 2100 * 2100 * 1300mm special sand box is used. The bottom is evacuated, and a temporary suction pipe is added in the middle. The large cone is arranged upwards. The riser is placed at the thickest part of the casting. Packing process:

1. Sandbox bottom sanding height 150-200mm, compact and flat
2. Placing a foam model in the middle of the sandbox
3. Assembly pouring system
4. Gaza to riser
5. Start the three-dimensional vibrating table
6. Assembly riser
7. Add sand to the top of the flask
8. Start the 3D vibrating table again
9. Plastic film
10. Lay a layer of dry sand on the film
11. Link negative pressure pipeline
12. Negative pressure
13. Waiting for pouring

Control and pouring of negative pressure

Start the vacuum pump before pouring, control the negative pressure in the range of 0.07-0.08MPa, and control the temperature in the range of 1420-1450 ° C. When pouring is started, pour a small flow point first to prevent the high-temperature metal liquid from spraying back and hurting people. Wait until the pouring system is burned through. Later, it was changed to high-flow pouring to ensure that the pouring port was always filled with metal liquid to avoid drawing air. In the final stage of pouring, it was changed to small-flow point pouring to facilitate the shrinkage of the casting and the riser was covered with a heat preservation agent. After the pouring is completed, keep the negative pressure for about 7 minutes, then open the plastic film, and continue to pump the negative pressure for about 10 minutes. The castings are kept in the sandbox for more than 24 hours before they can be removed from the box for cleaning.

The Lost Foam Casting result

After the casting is out of the box, the coating layer is peeled off automatically, which basically does not need manual cleaning, does not stick sand, the outer tapered surface of the casting is very smooth, and there are no common casting defects such as sand inclusions and air holes. The dimensional accuracy of the casting is accurate, the ovality is small, the machining allowance is small, and the process yield is high. (See following picture)

HP5 Cone Crusher Concave and Mantle semifinished product

Heat Treatment

The castings are installed in a furnace below 200 ° C, and heated to 550 ° C at a rate of 50 ° C / h for 3 hours, then 650 ° C and 2 hours, and then heated to 1050 ° C for 4 hours. The phase transition diagram of the manganese steel casting during heating shows that when heated to a temperature of about 550 ° C, some austenite is transformed into pearlite. When the temperature is maintained for about 3 hours, about 40% of the austenite is transformed into pearlite. The grains of the casting are further refined, and then processed according to the normal high-manganese steel heat treatment process, and the austenite grain size is refined to 1-2 grades. After solution treatment, the microstructure of high-manganese steel castings is a single-phase austenite structure, which has good toughness and non-magnetism. Its characteristics are: the surface layer will be rapidly processed under the impact of external force or contact stress Hardened with martensite formation, resulting in a highly wear-resistant surface layer, while the inner layer still maintains excellent impact toughness.

The Results

Our foundry supplies HAIKUANG company HP5 cone crusher liners with the same work-life as the original wear parts. But our price is much less than the original,