[0034] The invention relates to a surface hardening treatment method for titanium and titanium alloy ball valve sealing pairs and friction pairs. The surface hardening treatment method involves chemical heat treatment and vapor deposition hard coating, and the chemical heat treatment and vapor deposition hard coating are simultaneously applied to titanium And the sealing pair and friction pair of titanium alloy ball valve, which solves the problem of low surface hardness of titanium and titanium alloy ball valve after single chemical heat treatment. Due to the problem of poor hardness, the vapor-deposited hard coating further improves the bonding strength of the chemical heat treatment infiltration layer, and improves the hardness of the surface of titanium and titanium alloy ball valves. Even if the vapor-deposited hard coating is damaged during actual use, its The hardened layer formed by the chemical heat treatment infiltration layer can still play a protective role, achieving the purpose of double protection.
[0035] The above chemical heat treatment includes carburizing, oxygen infiltrating, plasma nitriding, sulfurizing, carbonitriding, nickel-chromizing, aluminizing and molybdenum infiltrating. CrN, or DLC, or TiCN, or TiAlN, or TiSiN, or AlCrN, or TiAlCrN, or TiAlSiN, or a combination of any two or more of the above-mentioned dielectric components, all of which The above-mentioned any two are, for example, a composition of TiN+CrN, and the any two or more are, for example, a composition of TiN+CrN+TiCN or a composition of TiN+CrN+...+TiCN.
[0036] It should be pointed out that titanium and titanium alloy ball valves include valve body, ball and valve seat. The sealing pair of titanium and titanium alloy ball valve refers to the relevant sealing parts of the valve body, ball and valve seat. Titanium and titanium alloys The friction pair of the ball valve refers to the relevant friction parts of the valve body, the ball body and each transmission and connection in the valve seat. The sealing pair and the friction pair actually cover the inner surface of the titanium and titanium alloy ball valve.
[0037] The surface hardening treatment method of the present invention is mainly aimed at the sealing pair and friction pair of titanium and titanium alloy ball valves. Titanium and titanium alloys are either TA1, or TA1ELI, or TA2, or TA2ELI, or TA3, or TA3ELI, or TA5, or TA10, or TC4, or TC4ELI, or TA16, or TA17, or TA22, or TA22-1, or TA23, or TA23-1, or TA24, or TA24 -1, or TA28, or TA31, or Gr.F2, or Gr.F5.
[0038] The features of the present invention are as follows:
[0039] Carry out inner surface cleaning treatment on the sealing pair and friction pair of titanium and titanium alloy ball valves. The surface cleaning treatment is a technique commonly used in the field, and then carry out carburizing, oxygen infiltration, plasma nitriding, sulfurizing, carbonitriding The chemical heat treatment methods of infiltration, nickel-chromium, aluminized and molybdenum infiltration, among the above chemical heat treatment methods:
[0040] The carburizing temperature is controlled at 800-1050°C, and the carburizing time is controlled at 2-6h;
[0041] The temperature of the oxygen infiltration is controlled at 600-900°C, and the time of the oxygen infiltration is controlled at 6-14 hours;
[0042] The temperature of the plasma nitriding is controlled at 450-970°C, and the time of the plasma nitriding is controlled at 36-60 hours;
[0043] The temperature of the sulfurizing is controlled at 500~700℃, and the time of the sulfurizing is controlled at 2~7h;
[0044] The temperature of the carbonitriding is controlled at 400-600°C, the time of the carbonitriding is controlled at 2-6h, and the mixing ratio of the carbonitriding is 2.5:1;
[0045] The temperature of the nickel-chromium infiltration is controlled at 700-900°C, the time of the nickel-chromium infiltration is controlled at 0.25-1.5h, and the mixing ratio of the nickel-chromium infiltration is 7:3;
[0046] The temperature of the aluminizing is controlled at 800~1000℃, and the time of the aluminizing is controlled at 3~15h;
[0047] The temperature of the molybdenum infiltration is controlled at 900-1100°C, and the time of the molybdenum infiltration is controlled at 2-10h;
[0048] The depth of the infiltration layer of the above chemical heat treatment is controlled to be more than 0.1mm, and the surface hardening hardness of the infiltration layer needs to be controlled at 500-1300HV after testing;
[0049] Then, the vapor-deposited hard coating of the infiltrated layer is carried out on the titanium and titanium alloy ball valve sealing pair and friction pair after the above chemical heat treatment under vacuum conditions. The vacuum degree under the condition is controlled at 10 -3 ~10 -4 Pa, the temperature of the vapor-deposited hard coating is controlled at 250-480°C, the time of the vapor-deposited hard coating is controlled at 5-20 h, the thickness of the vapor-deposited hard coating is controlled at 2-25 μm, and the vapor-deposited hard coating is controlled at 2-25 μm. The surface hardness of the layer should be controlled at 1100-2500HV after testing, the bonding strength of the vapor-deposited hard coating and the infiltrating layer should be controlled at 35-48MPa, and the insulation resistance of the vapor-deposited hard coating should be greater than 10KΩ. The coefficient of friction of the layer is less than 0.184.
[0050] The surface hardening treatment method of the present invention through the above chemical heat treatment + vapor deposition hard coating has the characteristics of environmental protection and no toxic pollutants, wherein chemical heat treatment is an excellent surface hardening technology, with high reliability, no environmental pollution, Low cost, short treatment period, wide applicability, easy to achieve local protection, high wear resistance and anti-seizure, good infiltration layer structure, stable product quality and other characteristics. The vapor deposition hard coating has the characteristics of a wide range of dielectric materials, high reactivity of deposition ions, low deposition process temperature, difficult deformation of titanium and titanium alloy ball valves, no pollution during deposition process, and environmental protection.
[0051] The working principle of the present invention is as follows:
[0052] Chemical heat treatment includes three processes: decomposition of chemical medium, absorption of active atoms and diffusion of atoms. At a certain temperature, the chemical medium undergoes a decomposition reaction and generates active atoms, which are adsorbed by the surface of the sealing pair and friction pair of the titanium and titanium alloy ball valve. After the surface absorbs the active atoms, the concentration of the chemical medium is greatly increased and a significant concentration gradient is formed. , Under the action of temperature, the active atoms diffuse in a direction along the direction of the concentration gradient, and as a result, a diffusion layer of a certain thickness can be obtained, thereby improving the surface hardening hardness of the sealing pair and friction pair of the titanium and titanium alloy ball valve. The increase in hardness also improves the wear resistance of the sealing pair and friction pair of the titanium and titanium alloy ball valve.
[0053] In order to further improve the surface hardening hardness and wear resistance of titanium and titanium alloy ball valve sealing pairs and friction pairs after chemical heat treatment, realize long-term sealing and wear resistance and meet the corrosion resistance requirements of different working conditions, vapor deposition technology is used in their A layer of hard coating is formed on the surface of the sealing pair and the friction pair. The vapor-deposited hard coating is to place the titanium and titanium alloy ball valve sealing pair and the relevant parts of the friction pair in a vacuum coating chamber. Beam, plasma, ion beam, laser beam, arc and other energy, gasify solid or liquid plating material into gaseous atoms, molecules or partial ionization into ions and deposit and condense on the cathode surface of titanium and titanium alloy ball valve sealing pair and friction pair, A vapor-deposited hard coat comprising the media components described above is prepared.
[0054] Through the surface hardening treatment of the above chemical heat treatment + vapor deposition hard coating, the problem of low surface hardness of titanium and titanium alloy ball valve sealing pairs and friction pairs after single chemical heat treatment is solved. On the basis of chemical heat treatment, the vapor deposition hard coating is adopted. It reduces the hardness difference of the chemical heat treatment layer, and the vapor deposition hard coating further improves the bonding strength of the chemical heat treatment layer and improves the hardness of the surface of titanium and titanium alloy ball valves. When the hard coating is damaged, the hardened layer formed by the chemical heat treatment infiltration layer can still play a protective role, achieving the purpose of double protection.
[0055]It should be noted that: in order to realize the long-term sealing effect of the sealing pair and friction pair of the titanium and titanium alloy ball valve, the medium components used in the vapor deposition hard coating must be combined with the actual corrosion conditions of the titanium and titanium alloy ball valve application. , according to the actual corrosion conditions, the medium composition used is either TiN, or CrN, or DLC, or TiCN, or TiAlN, or TiSiN, or AlCrN, or TiAlCrN, or TiAlSiN, or The composition of any two or more of the above-mentioned medium components, the composition is like a superimposed form of sandwich cake, when the medium component is a composite of any two and the actual corrosion condition is applicable to TiCN Coating TiN first and then coating TiCN. Similarly, when the medium component is any two or more composites and the actual corrosion conditions are applicable to TiCN, TiN is coated first, then CrN is coated, and then TiCN is coated. Three Each coating is a stacking process, just like the stacking form of a sandwich cake, and the total thickness of the stacking coating must be controlled within 2-25 μm.
