LeapZipBlog: gongda

gongda's blog

3 blogs

Satisfactory results were obtained by different surfacing processes

December 18, 2019 by gongda  

Use Method and Precautions of Wear Resistant Surfacing Electrode:

1. This welding rod cannot be used for surfacing welding of metal materials of gold, silver, copper and aluminum castings.

2. The overlaying welding layer of this welding rod cannot be machined by machine tool. If machining is needed, grinding machine or grinding wheel can be used. Not gas cutting, can only use cutting machine cutting.

3. Remove rust, oil and other impurities from butt welding parts before welding. If the weldment with strong impact needs to be heated and insulated.

4, try to use short arc small current welding, avoid burning loss of alloy elements.

5, surfacing metal alloy content is extremely high, can be multilayer surfacing, general surfacing 1-3 layers.

6. During multi-layer surfacing, the welding can be completed at one time when it is hot. It is best to put it into lime powder for heat preservation when it is hot. Its wear resistance will not change and its impact resistance will be improved.

7. If surfacing welding is to be carried out again in the future, the initial welding can be carried out at the position where the original welding layer is ground, and it is better to gradually weld the welded parts at one time, so as to avoid the falling off of the original remaining welding layer caused by rapid heating and rapid cooling.

8. If the welding rod is affected with damp, air holes will appear in the welding layer locally, so that the welding rod can be dried. It is better to use it for 1-2 hours above 500℃. Surfacing is a welding process in which a wear-resistant, corrosion-resistant and heat-resistant metal layer is deposited on the surface or edge of the workpiece. It has obvious economic benefits for repairing and prolonging the service life of parts, reasonably using materials, improving product performance and reducing cost.

The surfacing work and working conditions are very complicated, and suitable welding rods must be selected according to different requirements. Different workpieces and surfacing electrodes must adopt different surfacing processes to obtain satisfactory surfacing results.

 

For more information, you can click here: Heat Resistant Steel Castings.

What should casting manufacturers pay attention to in the production process?

December 11, 2019 by gongda  

Stainless steel castings are no stranger to us, but it is difficult to control the size in our production process. Any carelessness will result in inaccurate size. So what are the factors that make it inaccurate in size? The main factors are as follows.

1. Structure of the casting: the wall of the casting is thick, the shrinkage rate is large, the wall of the casting is thin, and the shrinkage rate is small. 2. Shell-making materials: zircon sand, zircon powder, Shangdian sand and Shangdian powder are used, because their expansion coefficient is small, it is only 4.6×10-6/℃.

3. Roasting of shell: due to the small expansion coefficient of stainless steel casting shell, when the shell temperature is 1150℃, it is only 0.053%.

4. Casting temperature: the higher the pouring temperature, the greater the shrinkage rate, the lower the pouring temperature, the shrinkage 5. Casting material: the higher the carbon content in the material, the smaller the linear shrinkage rate of stainless steel castings, the lower the carbon content, the greater the linear shrinkage rate of stainless steel castings.

6. Linear shrinkage rate of casting caused by molding: wax injection temperature, wax injection pressure and holding time have the most obvious influence on the size of the investment mold, followed by wax injection pressure. Holding time has little influence on the final size of the investment mold after the investment mold is formed. Linear shrinkage rate of wax material is about 0.9-1.1%.

All of the above will affect the dimensional accuracy of stainless steel castings, therefore, we should pay special attention in the future production process.

 

Shenyang Gongda Heavy Equipment Manufacturing Co., Ltd., A Prominent and Highly Recognized Manufacturers and Suppliers of High Quality Metal Castings. For more information on castings, please contact us: https://www.wearresistantcasting.com/

What should casting manufacturers pay attention to in the production process?

December 11, 2019 by gongda  

Stainless steel castings are no stranger to us, but it is difficult to control the size in our production process. Any carelessness will result in inaccurate size. So what are the factors that make it inaccurate in size? The main factors are as follows.

1. Structure of the casting: the wall of the casting is thick, the shrinkage rate is large, the wall of the casting is thin, and the shrinkage rate is small. 2. Shell-making materials: zircon sand, zircon powder, Shangdian sand and Shangdian powder are used, because their expansion coefficient is small, it is only 4.6×10-6/℃.

3. Roasting of shell: due to the small expansion coefficient of stainless steel casting shell, when the shell temperature is 1150℃, it is only 0.053%.

4. Casting temperature: the higher the pouring temperature, the greater the shrinkage rate, the lower the pouring temperature, the shrinkage 5. Casting material: the higher the carbon content in the material, the smaller the linear shrinkage rate of stainless steel castings, the lower the carbon content, the greater the linear shrinkage rate of stainless steel castings.

6. Linear shrinkage rate of casting caused by molding: wax injection temperature, wax injection pressure and holding time have the most obvious influence on the size of the investment mold, followed by wax injection pressure. Holding time has little influence on the final size of the investment mold after the investment mold is formed. Linear shrinkage rate of wax material is about 0.9-1.1%.

All of the above will affect the dimensional accuracy of stainless steel castings, therefore, we should pay special attention in the future production process.

 

Shenyang Gongda Heavy Equipment Manufacturing Co., Ltd., A Prominent and Highly Recognized Manufacturers and Suppliers of High Quality Metal Castings. For more information on castings, please contact us: https://www.wearresistantcasting.com/