Common process of cutting TC4 titanium alloy plate and TC4 pure titanium plate

In the cutting of TC4 titanium plate and titanium alloy plate, the common process flow and content are described as follows:
(1) If it is a semi-automatic cutting, the guide rail should be placed on the plane of the titanium plate, and then the cutting machine should be placed on the guide rail. Note that the order cannot be reversed.
(2) The cutting parameters should be appropriate, and should be reasonably determined according to the thickness of the titanium plate, etc., so as to obtain a good cutting effect.
(3) Check whether the nozzle gas is unblocked, and unblock it if necessary.
(4) Before cutting, the surface of the titanium plate should be cleaned, and a certain space should be left, which can help the slag blow out.
(5) The distance between the cutting tip and the surface of the titanium plate should be appropriate. It is not good to be too close or too far.
(6) The preheating of the titanium plate should be sufficient to avoid affecting the cutting process.
(7) If cutting workpieces of different sizes, cut small pieces first and then large pieces.
According to the data of titanium plate manufacturers, titanium is a new type of metal. The performance of titanium is related to the content of impurities such as carbon, nitrogen, hydrogen, and oxygen. The purest titanium iodide impurity content does not exceed 0.1%, but its strength is low and its plasticity is high. . The properties of 99.5% industrial pure titanium are: density ρ = 4.5g / cm3, melting point 1725 ° C, thermal conductivity λ = 15.24W / (mK), tensile strength σb = 539MPa, elongation δ = 25%, section shrinkage The rate ψ = 25%, the elastic modulus E = 1.078 × 105MPa, and the hardness HB195.
(1) higher than intensity
The density of titanium alloy is generally about 4.5g / cm3, which is only 60% of steel. The strength of pure titanium is close to that of ordinary steel. Some high-strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength / density) of the titanium alloy is much greater than that of other metal structural materials. See Table 7-1. Parts and components with high unit strength, good rigidity, and light weight can be produced. Currently, titanium alloys are used in aircraft engine components, skeletons, skins, fasteners, and landing gear.
(2) High thermal strength
The operating temperature is several hundred degrees higher than that of aluminum alloys, and the required strength can be maintained at moderate temperatures. The two types of titanium alloys can work for a long time at a temperature of 450 to 500 ° C. The two types of titanium alloys are still very high in the range of 150 to 500 ° C. Specific strength, while the specific strength of aluminum alloy significantly decreased at 150 ° C. The working temperature of titanium alloy can reach 500 ℃, while that of aluminum alloy is below 200 ℃.
(3) Good corrosion resistance
Titanium alloy works in humid atmosphere and seawater medium, and its corrosion resistance is far better than that of stainless steel. It is particularly resistant to pitting, acid, and stress corrosion; organic objects such as alkali, chloride, and chlorine, nitric acid, and sulfuric acid Etc. Have excellent corrosion resistance. However, titanium has poor resistance to reducing oxygen and chromium salt media.
(4) Good low temperature performance
Titanium alloy can maintain its mechanical properties at low and ultra-low temperatures. Low temperature performance, titanium alloys with very low interstitial elements, such as TA7, can still maintain a certain degree of plasticity at -253 ℃. Therefore, titanium alloy is also an important low temperature structural material.
(5) High chemical activity
Titanium has a large chemical activity and produces a strong chemical reaction with O, N, H, CO, CO2, water vapor, ammonia, etc. in the atmosphere. When the carbon content is greater than 0.2%, hard TiC will be formed in the titanium alloy; when the temperature is higher, it will also form a TiN hard surface layer when interacting with N; when the temperature is above 600 ° C, titanium absorbs oxygen to form a hardened hard layer ; Increased hydrogen content will also form a brittle layer. The depth of the hard and brittle surface layer generated by absorbing gas can reach 0.1 to 0.15 mm, and the degree of hardening is 20% to 30%. Titanium also has a large chemical affinity and is prone to adhere to friction surfaces.
(6) Small thermal conductivity and small elastic modulus
The thermal conductivity of titanium is λ = 15.24W / (m.K) is about 1/4 of nickel, 1/5 of iron, 1/14 of aluminum, and the thermal conductivity of various titanium alloys is about 50% lower than that of titanium. The elastic modulus of titanium alloy is about 1/2 that of steel, so its rigidity is poor and it is easy to deform. It is not suitable to make slender rods and thin-walled parts. The springback of the machined surface during cutting is large, about 2 to 3 of stainless steel. Times, causing severe friction, adhesion, and abrasion on the flank of the tool.

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