GB/T 2965-2023 Titanium and Titanium Alloy Bars – Chinese National Standard

Titanium and Titanium Alloy Bars

Scope This document specifies the classification and marking, technical requirements, test methods, inspection rules, marking, packaging, transportation, storage, accompanying documents, and order content for titanium and Lega di titanio bars. This document is applicable to round and rectangular bars of titanium and titanium alloys produced by forging and rolling.

Normative References The contents of the following documents constitute essential clauses of this document through normative references in the text. For dated references, only the version corresponding to that date applies to this document. For undated references, the latest version (including all amendments) applies to this document.

• GB/T 228.1-2021: Metallic Materials—Tensile Testing—Part 1: Method of Test at Room Temperature
• GB/T 228.2: Metallic Materials—Tensile Testing—Part 2: Method of Test at Elevated Temperature
• GB/T 2039: Metallic Materials—Uniaxial Tensile Creep Testing Method
• GB/T 3620.1: Designation and Chemical Composition of Titanium and Titanium Alloys
• GB/T 3620.2: Chemical Composition Permissible Variations for Titanium and Titanium Alloy Processed Products
• GB/T 4698 (All Parts): Methods for Chemical Analysis of Spugna Titanio, Titanium, and Titanium Alloys
• GB/T 5168: Methods for Macro and Microstructural Examination of Titanium and Titanium Alloys
• GB/T 5193: Ultrasonic Testing Methods for Titanium and Titanium Alloy Processed Products
• GB/T 6611: Terminology and Metallographic Atlas for Titanium and Titanium Alloys
• GB/T 8180: Packaging, Marking, Transportation, and Storage of Titanium and Titanium Alloy Processed Products
• GB/T 23604: Sampling Methods for Mechanical Property Tests of Titanium and Titanium Alloy Products
• GB/T 23605: Determination Method for Transformation Temperature of Titanium Alloys
• GB/T 34647: Codes for Conditions of Titanium and Titanium Alloy Products
• GB/T 38982: Methods for Dimension Inspection of Titanium and Titanium Alloy Processed Products
• GB/T 39799: Dimensions, Shapes, Weights, and Permissible Variations for Titanium and Titanium Alloy Bars and Wires
• YS/T 1262: Methods for Chemical Analysis of Sponge Titanium, Titanium, and Titanium Alloys—Determination of Multi-element Content by Inductively Coupled Plasma Atomic Emission Spectrometry

Terms and Definitions The terms and definitions defined in GB/T 6611, GB/T 34647, and GB/T 38982 are applicable to this document.

4 Classification and Marking

4.1 Product Classification The grades, conditions, and specifications of the bar products should comply with the provisions in Table 1.

Table 1.

Grado	Condizione	Diameter or Section Thickness (mm)	Lunghezza (mm)
TA1	Hot Worked (R)	7 – 100	300 – 6000
TA2	Cold Worked (Y)	7 – 100	300 – 5000
TA3	Ricotto (M)	7 – 100	300 – 6000
TA1G	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA2G	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA3G	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA4G	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA5	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA6	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA7	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA9	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA10	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA13	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA15	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA18	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TA19	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TB2	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TB6	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC1	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC2	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC3	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC4	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC4EL1	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC6	Ricotto (M) (Standard Annealing)	7 – 100	300 – 6000
TC9	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC10	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC11	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC12	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC17	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC18	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC21	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000
TC25	Hot Worked (R), Cold Worked (Y)	7 – 100	300 – 6000

Nota:

• TA19 and TC9 titanium alloy bars are supplied in hot-worked (R) and cold-worked (Y) conditions.
• The annealed (M) condition for TC6 titanium alloy bars refers to standard annealing.

4.2 Product Marking

The product marking should be represented in the sequence of product name, grade, condition, specification, and document number.

Example 1: For a round bar made of TA2 grade, in an annealed condition, with a diameter of 100mm and a length of 3000mm to 4000mm, the marking would be: Bar TA2M 100 × (3000~4000) GB/T 2965-2023

Example 2: For a square bar made of TC4 grade, in a hot worked condition, with a section thickness of 90mm and a length of 2000mm, the marking would be: Bar TC4R 90 × 2000 GB/T 2965-2023

Example 3: For a round bar made of TC4 grade, in a hot worked condition, with a diameter of 80mm and a length of 3000mm, the marking would be: Bar TC4R 80 × 3000 GB/T 2965-2023

5 Technical Requirements

5.1 Composizione chimica 5.1.1 The chemical composition of the bars should comply with the provisions of GB/T 3620.1. 5.1.2 When the purchaser takes samples from the product for chemical composition reinspection, the permissible variations in chemical composition should comply with the provisions of GB/T 3620.2.

5.2 Dimensions and Permissible Variations The dimensions and permissible variations of the bars should comply with the provisions of GB/T 39799.

5.3 Mechanical Properties 5.3.1 The mechanical properties of the bars should be tested on specimens after heat treatment. The recommended heat treatment regimes for the specimens are given in Appendix A. 5.3.2 The room temperature tensile properties of the bars should comply with the provisions of Table 2. When required by the purchaser and stated in the order, the high-temperature mechanical properties of certain grades of bars should comply with the provisions of Table 3.

Table 2 Room Temperature Tensile Properties

Grado	Tensile Strength (R<sub>m</sub>) (MPa)	Yield Strength (R<sub>p0.2</sub>) (MPa)	Elongation after Fracture (A) (%)	Reduction of Area (Z) (%)	Remarks
TA1	370	250	20	30
TA2	440	320	18	30
TA3	540	410	15	25

Grado	Tensile Strength (R<sub>m</sub>) (MPa)	Yield Strength (R<sub>p0.2</sub>) (MPa)	Elongation after Fracture (A) (%)	Reduction of Area (Z) (%)	Remarks
TA1G	240	140	25	30
TA2G	400	275	20	30
TA3G	500	380	18	25
TA4G	580	485	15	25
TA5	685	585	13	25
TA6	685	585	13	25
TA7	785	680	10	20
TA9	370	250	20	30
TA10	485	345	18	25
TA13	540	400	15	25
TA15	885	825	10	15
TA18	620	518	12	25
TA19	895	825	10	15
TB2	<980	825	10	20
TB6	1,370	1,100	10	15
TC1	1,105	1,035	15	30	Solution treatment
TC2	585	460	25	30	Solution aging treatment
TC3	685	560	10	25
TC4	800	680	10	25
TC4ELI	895	825	10	15
TC6	980	840	10	25	Regular annealing for TC6 bars
TC9	1,060	910	10	25
TC10	1,030	900	10	25
TC11	1,030	910	10	25
TC12	1,150	1,000	10	25
TC17	1,120	1,030	10	25
TC18	1,080 – 1,280	1,010	10	25
TC21	1,100	1,000	10	25
TC25	980	925	10	25

Nota: The properties of TC6 bars are measured in the standard annealed state. If requested by the purchaser and stated in the order, the properties can be measured in the isothermal annealed state.

Table 3. high-temperature mechanical properties

Grado	Test Temperature (° C.)	Tensile Strength (R<sub>m</sub>) (MPa)	Test Stress (σ) (MPa)	Test Duration (h)
TA6	350	420	390	100
TA7	350	490	440	100
TA15	500	570	470	50
TA18	350	340	320	100
TA19	400	310	280	100
TC1	480	620	480	35
TC2	350	345	325	100
TC4	350	420	390	100
TC6	400	685	560	100
TC9	400	785	685	50
TC10	500	835	590	100
TC11	400	685	785	35
TC12	500	885	640	100
TC17	500	735	590	100
TC25	400	685	685	50

Nota: If the long-term performance of TC11 titanium alloy bars does not meet the requirements, it is permissible to conduct a test at 500°C with a test stress of 590 MPa for ≥100 hours. If this test passes, the batch of bars is considered to meet the long-term performance requirements.

5.4 Transition Temperature Upon request and specification in the purchase order, the bars should provide the transition temperature B according to the smelting furnace number.

5.5 Ultrasonic Testing Upon request and specification in the purchase order, the bars should undergo ultrasonic testing. The acceptance level shall be determined through negotiation between the supplier and the purchaser.

5.6 Low Magnification Microstructure The low magnification microstructure of the bars should be free from cracks, shrinkage, porosity, metal or non-metallic inclusions, segregation affecting use, and other visible metallurgical defects.

5.7 Microstructure Upon request and specification in the purchase order, the material should undergo evaluation of microstructure. The evaluation requirements shall be determined through negotiation between the supplier and the purchaser.

5.8 Appearance Quality 5.8.1 Bars should be supplied with a polished surface. The surface roughness (Ra) of the bars should not exceed 3.2μm. 5.8.2 Minor scratches, indentations, pits, wrinkles, and other defects on the surface of the bars are allowed, provided they do not exceed half of the allowable deviation in diameter or thickness. 5.8.3 Local defects on the surface of the material should be removed. The depth of cleaning should not exceed the allowable deviation of the corresponding dimension of the product. The ratio of depth to width of the cleaned area should not exceed 1:6.

6. Test Methods

6.1 Chemical Composition The chemical composition analysis of the product should be conducted in accordance with the provisions of GB/T4698 (all parts) or YS/T1262, and arbitration analysis should be carried out according to the provisions of GB/T4698 (all parts).

6.2 Dimensions and Permissible Variations The measurement of the product’s dimensions and permissible variations should be carried out according to the provisions of GB/T38982.

6.3 Room Temperature Tensile Properties The test of the product’s room temperature tensile properties should be conducted according to the provisions of GB/T228.1-2021. The R7 specimen should be used for testing.

6.4 High-Temperature Tensile Properties The test of the product’s high-temperature tensile properties should be conducted according to the provisions of GB/T228.2.

6.5 Persistent Performance The test of the product’s persistent performance should be conducted according to the provisions of GB/T2039.

6.6 B Transition Temperature The test of the product’s B transition temperature should be conducted according to the provisions of GB/T23605.

6.7 Ultrasonic Testing The ultrasonic testing of the product should be conducted according to the provisions of GB/T5193.

6.8 Low Magnification and Microstructure The inspection of the product’s low magnification and microstructure should be conducted according to the provisions of GB/T5168.

6.9 Appearance Quality The appearance quality of the product should be inspected visually. The surface roughness of the bars should be inspected using the standard sample block comparison method.

7.1 Inspection and Acceptance

7.1.1 The products shall be inspected by the supplier or a third party to ensure that the product quality meets the requirements of this document and the order.

7.1.2 The buyer may inspect the received products according to the provisions of this document. If the inspection results do not conform to the provisions of this document or the order, they shall be notified to the supplier in writing and resolved through negotiation between the two parties. Objections to the shape and size and their allowable tolerances, and the appearance quality shall be raised within one month from the date of receipt of the products; objections to the chemical composition, mechanical properties, low-power organization, microstructure, and ultrasonic testing shall be raised within three months from the date of receipt of the products. In case of arbitration, the buyer and the supplier shall jointly sample or reach an agreement on sampling.

7.2 Batching

Products shall be submitted for acceptance in batches, each batch consisting of products of the same brand, heat number, specification, manufacturing method, state, and heat treatment batch.

7.3 Inspection Items

Each batch of products shall be inspected for chemical composition, shape and size and their allowable tolerances, tensile properties at elevated temperature, low-power organization and appearance quality. High-temperature mechanical properties, transition temperature, ultrasonic testing and microstructure shall also be inspected when specified in the order.

7.4 Sampling

Product sampling shall comply with the provisions of Table 4.

Product type	Sampling method
Bars, aste, tubi, profiles, strisce, and plates	Take samples from each batch, and the sampling location shall be evenly distributed along the length of the product. The number of samples shall be determined according to the following table:
	Batch size (T)
	≤50
	51-100
	101-200
	>200
Forgings and castings	Take samples from each batch, and the sampling location shall be representative of the product quality. The number of samples shall be determined according to the following table:
	Batch size (pieces)
	≤50
	51-100
	101-200
	>200
Welded products	Take samples from each batch of welds, and the sampling location shall be representative of the weld quality. The number of samples shall be determined according to the following table:
	Batch size (m)
	≤50
	51-100
	101-200
	>200

7.5 Judgment of Inspection Results

7.5.1 If the chemical composition test results do not meet the requirements, the batch of products shall be judged unqualified.

7.5.2 If the test results for shape and size and their allowable tolerances, test ad ultrasuoni, and appearance quality are not qualified, the corresponding product shall be judged unqualified. Tuttavia, the supplier may remove the unqualified parts and re-inspect them. If they are qualified, they shall be re-batched and delivered.

7.5.3 If the mechanical performance test results are not qualified, double the number of test pieces shall be taken from the batch of products for retesting. If one test piece is still unqualified after retesting, the batch of products shall be judged unqualified. Tuttavia, the supplier may inspect each product individually, and those that are qualified shall be re-batched and delivered. Alternatively, the products may be re-heat treated and re-sampled for inspection.

7.5.4 If the low-power organization and microstructure test results are not qualified, the batch of products shall be judged unqualified.

8 Marking, Packaging, Transportation, Storage, and Accompanying Documents

8.1 Marking

8.1.1 Product Marking

Qualified products shall be marked (or labeled) with the following information:

a) Supplier name; b) Brand; c) Specifica; d) State; e) Batch number; f) Document number.

8.1.2 Packaging Marking

The packaging marking of the products shall comply with the provisions of GB/T8180.

8.2 Packaging, Transportation, and Storage

The packaging, transportation, and storage of the products shall comply with the provisions of GB/T8180.

8.3 Accompanying Documents

Each batch of products shall be accompanied by accompanying documents, Quale, in addition to the supplier information, product information, document number, and date of manufacture or packaging, should also include the following:

a) Quality certificate, which shall include the following contents: Product name, brand, specification and state; Prodotto ingot number, batch number, batch weight and quantity; Main performance and technical parameters of the product; Analytical inspection results and quality inspection department seal; Others.

b) Certificate of conformity, which shall include the following contents: Ingot or batch number; Inspection date; Inspector’s signature or seal; Others.

c) Others.

9 Contents of Order Form

The buyer may, according to its own needs, list the following contents in the order form for the products listed in this document:

a) Product name; b) Brand; c) Specifica; d) State; e) Weight; f) Quantity; g) Document number; h) Others.