GB/T 2965-2007 TC4 titanium alloy rod GB: 5 core points

GB/T 2965-2007 Titanium and Titanium Alloy Bars is the core executive standard for TC4 titanium alloy rod procurement in China., TC4 corresponds to Gr5, It is also the largest market consumption at present, Titanium alloy grades with the widest application scenarios, Widely used in aviation structural parts, medical implant, Marine engineering and high-end chemical equipment.In this paper, combined with Baoji China titanium valley industry practical experience, 5 core points to comb TC4 titanium alloy rod procurement must master, Help purchasing and technical staff understand standards, Standardize material selection and acceptance.

Point 1: Scope of application GB/T 2965-2007 is applicable to hot forging, hot rolling, Titanium and titanium alloy bars produced by extrusion. Specification coverage: diameter Φ10-300mm, length up to 6000mm, length can be customized on demand;Including round rod, hexagonal rod, square rod a variety of profile categories. At the same time, it is clear that the standard does not apply to the product range, Diameter Φ≤10mm titanium wire, The implementation standard is GB/T 3623TC4ELI bars for medical use shall comply with GB/T 13810;high puritytitanium barGB/T 3620.2 shall be followed.

Point 2: Chemical composition of TC4 grade The standard clearly defines the chemical composition of TC4 titanium alloy, and titanium is used as the residual element of the matrix;Al content range 5.5%-6.8%;Vanadium content range 3.5%-4.5%;The maximum iron content shall not exceed 0.30%;Carbon ≤0.10%;Nitrogen ≤0.05%;Hydrogen ≤0.015%;Oxygen ≤0.20%. The role of each element: aluminum is a strengthening element, which can enhance the high temperature strength of the alloy;Vanadium can stabilize β phase and improve material plasticity.Oxygen is an interstitial element, which directly affects the balance between strength and plasticity of titanium alloys.

Point 3: Mechanical properties Annealed state TC4 bar mechanical properties specified in the national standard: tensile strength ≥895 MPa, yield strength ≥825 MPa, elongation ≥10%, reduction of area ≥25%. Horizontal comparison of other titanium grades: TA2Titanium PlateTensile strength ≥400MPa, TC4 strength is about 2.2 times of TA2;TA10 tensile strength is also ≥400MPa, TC4 mechanical properties far exceed TA10;TC4ELI tensile strength ≥860MPa, strength slightly lower than TC4, but better plasticity. The core performance characteristics of TC4 are high strength with medium plasticity, and it is a structural titanium alloy with outstanding comprehensive performance.

Point 4: Heat treatment state GB/T 2965-2007 specifies two main supply states.Annealed state (M), is also the most commonly used procurement state, high material strength, moderate plasticity;Solid solution + aging state (STA), the material strength is further improved, and the tensile strength can reach more than 1100MPa. Applicable scenarios for different states, Annealed state can be used for aerospace structural parts, medical implant, chemical equipment, Covers approximately 90% of application scenariosSolution aging state is mostly used for ultra-high strength structural parts and key load-bearing parts of equipment.Procurement attention, Standard default delivery state is annealed state, if solution age treatment is required, It needs to be agreed with the supplier in advance.

Point 5: Inspection rules The standard stipulates 6 mandatory inspection items: chemical composition analysis according to furnace number;Mechanical property detection, including tensile, yield, extension, reduction of area index;Macroscopic examination at low magnification;high-power metallographic examination;Products with important uses must undergo ultrasonic inspection;size measurement and surface quality inspection. Ultrasonic flaw detection is divided into four levels: AA level requirements are the most stringent, used for aviation, medical key components;Class A standards are strict and are mostly used for aviation structural parts;Class B is a conventional high standard, suitable for high-end chemical and marine engineering;Class C is a general industrial grade. Procurement acceptance reference suggestions: aviation field to select AA or A level flaw detection;TC4ELI shall be selected for medical implants and GB/T 13810 shall be implemented;Class B flaw detection shall be selected for chemical engineering and marine engineering.For each batch of products, the supplier shall provide quality assurance certificate, ultrasonic inspection report and metallographic inspection report simultaneously.

TC4 bar main application areas TC4 titanium alloy rod application scene rich, aerospace field, engine components, fuselage structure, Various types of fastenersMedical device field, bone plate, bone nail, hip joint, dental implant;Ocean engineering field, deep sea drilling equipment, diving supporting components;Chemical equipment field, high pressure reactor, heat exchanger;Automotive industry, connecting rods, fasteners, racing high-performance parts.

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