At the end of the 1980s, the low temperature chemical vapor deposition (PCVD) technology developed by Krupp.Widia reached a practical level. The processing temperature has been reduced to 450-650 ° C, which effectively suppresses the generation of η phase. It can be used for thread cutters and milling cutters. The molds are coated with TiN, TiCN, TiC, etc., but so far, the PCVD process has not been widely used in the field of tool coating. In the mid-1990s, the emergence of new technologies for medium temperature chemical vapor deposition (MT-CVD) revolutionized CVD technology. MT-CVD technology is a new process for the decomposition and chemical reaction of TiCL4, H2 and N2 at 700-900 °C to form TiCN with C/N organic acetonitrile (CH3CN) as the main reaction gas. The coating of dense fibrous crystalline form can be obtained by MT-CVD technology, and the coating thickness can reach 8-10 μm. The coating structure has high wear resistance, thermal shock resistance and toughness, and can be deposited on the surface of the blade by high temperature chemical vapor deposition (HT-CVD) process, such as Al2O3, TiN, etc. A material with low material affinity and good self-lubricating properties. The MT-CVD coated inserts are suitable for use in high speed, high temperature, high load, dry cutting conditions and have a life expectancy that is approximately double that of conventional coated inserts. At present, CVD (including MT-CVD) technology is mainly used for the surface coating of cemented carbide turning tools, and the coating tool is suitable for high speed roughing and semi-finishing of medium and heavy cutting. CVD technology can also achieve α-Al2O3 coating, which is currently difficult to achieve PVD technology, so CVD coating technology still plays an important role in dry machining.
The technology appeared in the late 1970s and can be used as a final treatment process for the coating of high speed steel tools because its process temperature can be controlled below 500 °C. Since the PVD process can greatly improve the cutting performance of high-speed steel tools, the technology has been rapidly popularized since the 1980s. By the end of the 1980s, the proportion of PVD coatings for high-speed steel complex tools in industrialized countries has exceeded 60%. . The successful application of PVD technology in the field of high-speed steel tools has attracted the attention of manufacturing industries all over the world. People are competing to develop high-performance and high-reliability coating equipment, and also expand their application fields, especially in cemented carbide. The application in ceramic tools has been further studied. The results show that compared with the CVD process, the PVD process has a low processing temperature, and has no effect on the flexural strength of the tool material below 600 °C (test results are shown in Table 1); the internal stress state of the film is compressive stress, which is more suitable for The coating of cemented carbide precision complex tools; PVD process has no adverse impact on the environment, in line with the development direction of modern green manufacturing. With the advent of the era of high-speed machining, the proportion of high-speed steel tool applications has gradually declined, and the proportion of applications of cemented carbide tools and ceramic tools has become an inevitable trend. Therefore, industrialized countries have been working on cemented carbide tools since the early 1990s. Research on PVD coating technology has made breakthroughs in the mid-1990s. PVD coating technology has been widely used in carbide end mills, drill bits, step drills, oil hole drills, reamers, taps, and indexable Coating treatment of milling inserts, profiled tools, welding tools, etc.
Table 1 Effect of PVD Coating on Bending Strength of Cemented Carbide Materials at Different Temperatures Carbide Grade - Average Bending Strength (MPa) - Uncoated - Coating (300 ° C) - Coating (600 ° C) - Coated Layer (700 ° C) M20-2109-2266-2129-2059M30-2285-2469-2370-
At present, PVD technology not only improves the bonding strength between the film and the tool base material, but also the coating composition from the first generation of TiN to the multi-composite coating of TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, TiN-AlN, CNx, etc. Floor. The emergence of nanoscale coatings such as ZX coatings (ie TiN-AlN coatings) has made a new breakthrough in the performance of PVD coated tools. The new coating has high bonding strength with the substrate, the hardness of the coating film is close to CBN, the oxidation resistance is good, the peeling resistance is strong, and the surface roughness of the tool can be significantly improved, and the shape and precision of the cutting edge of the precision tool are effectively controlled. Precision machining quality is comparable to uncoated tools.
After decades of research and development, various tool coating processes have been widely used in hard alloy and high speed steel cutting tools. The main development stages and application fields of the coating process are shown in Table 2.
Table 2 Main coating process development period and application time Time - Coating composition - Coating method - Main application fields Year - TiC, TiN-CVD - Carbide tool, mold coating year - TiCN, TiC + Al2O3-CVD- Carbide tool, mold coating year-TiN-PVD-High speed steel tool coating year-TiC+Al2O3+TiN, Al-ON-CVD-Carbide tool coating year-TiCN-MT-CVD-carbide Tool Coating Year-TiCN-PVD-Carbide, HSC Milling, Drill Tool Coating Year-Diamond, CBN-CVD, PVD-Carbide Tool Coating Year-TiAlN-PVD-Carbide Milling Cutter Coating (for steel, cast iron processing)
Year - TiN, TiCN, TiC-PCVD - mold, thread cutter, milling cutter, etc. - TiAlN + CrC - PVD - car, milling titanium alloy year - TiN + TiCN (CVD) + TiN (PVD) - CVD + PVD - hard Alloy Milling Tools Year-CrN-PVD-Titanium Alloy, Copper Alloy Processing Year-MoS2-PVD-High Speed ​​Steel Complex Tool Coating Year-TiN-AlN-PVD-Carbide Milling Blade Coating Year-Thick Film Fiber TiCN-MT-CVD-Carbide Turning Tool Coating (for rough and semi-finishing)
Year-CNx-CVD, PVD-High Speed ​​Steel Tool Coating Year-TiAlCN-PVD-Carbide Blade Coating
Previous Next
PTO Gear Pump is one kind of arc gear pump, it's also be called on-board gear pump. this kind of pump have big flow rate range and high pressure. pump can be used to transfer many kind of oil. like: gasoline, diesel fuel oil, kerosene, lube oil, engine oil etc. pump can be driven by truck engine, also can be driven by electric motor, diesel engine and gasoline engine. pump is small in size and easy to disassemble,Low price and wide application range,widely used in various industries.
PTO Gear Pump,PTO Driven Gear Pump,PTO Fuel Oil Gear Pump,Electric PTO Gear Pump
Botou Honghai Pump Co.,Ltd , https://www.pumphonghai.com