GB/T 3624-2010Titanium and titanium alloy seamless tubes (English PDF)

3.1 Classification of products

3.1.1 Designation, status and specification of products

t - Nominal wall thickness of the tube, in millimeters (mm);

D - Nominal outer diameter of the tube, in millimeters (mm);

e - Constant, when the tube's diameter is less than or equal to 25.4 mm, e

takes 0.04; when the tube's diameter is greater than 25.4 mm, e takes 0.06.

3.4.1.2 When the tubes of D/t < 10 are subjected to flattening test, the crack

generated at the position corresponding to "6 o'clock" and "12 o'clock" on the

inner surface of the tube shall not be used as the basis for rejection.

3.4.2 Hydraulic (pneumatic) pressure test

3.4.2.1 When the purchaser requests and indicates in the contract (or the order

form), the tube shall be subjected to the hydraulic pressure or pneumatic

pressure test. The test method selected by the purchaser shall be indicated in

the contract (or order form). Where it is not indicated in the contract (or the order

form), the supplier may not conduct the test, but must ensure that it meets the

requirements for the minimum hydraulic pressure in 3.4.2.2 or the pneumatic

pressure test in 3.4.2.3.

3.4.2.2 When the hydraulic test is carried out, the test pressure selected by the

purchaser shall be indicated in the contract (or order form). When not specified

in the contract (or order form), the test pressure is calculated according to the

following formula (2).

Where.

p - Test pressure, in Megapascal (MPa);

S - Allowable stress, which takes 50% of the minimum specified non-

proportional extension strength, in Megapascal (MPa);

D - Nominal outer diameter of the tube, in millimeters (mm);

t - Nominal wall thickness of the tube, in millimeters (mm).

When the nominal outer diameter of the tube is not more than 76 mm, the

maximum pressure of the hydraulic test is not more than 17.2 MPa; when the

nominal outer diameter of the tube is greater than 76 mm, the maximum

pressure of the hydraulic test is not more than 19.3 MPa. The pressure shall be

maintained for 5 s during the test, the tube shall be free from distortion or

leakage.

3.4.2.3 During the pneumatic pressure test, the pressure of the internal

use the S8 specimens in GB/T 228.For the tubes which have outer diameter

greater than 35 mm, it shall use the S4 specimen.

4.3 Test method of process performance

4.3.1 Tube's flattening test shall be carried out according to GB/T 246.

4.3.2 Tube's hydraulic pressure test shall be carried out according to GB/T 241.

4.3.3 Tube's pneumatic pressure test shall be carried out according to the

method approved by both parties.

4.3.4 Tube's bending test shall be carried out according to GB/T 244.

4.4 Measurement method of dimension

The dimensional inspection of the tube is carried out by the use of a gauge of

corresponding accuracy.

4.5 Inspection method of appearance quality

The appearance quality of the tube is checked by visual inspection.

5.1 Inspection and acceptance

5.1.1 The product shall be inspected by the supplier's quality inspection

department, to ensure that the product's quality meets the requirements of this

standard or contract (or purchase order). Meanwhile it shall fill in the quality

certificate.

5.1.2 The products received by the purchaser shall be inspected and accepted

according to the provisions of this standard. If the inspection results are

inconsistent with the provisions of this standard, they shall be submitted to the

supplier within three months from the date of receipt of the product, to be settled

by the supplier and the purchaser through negotiation. If arbitration is required,

the arbitration sampling shall be carried out jointly by the supplier and the

purchaser.

5.2 Group-batch

Products shall be submitted for acceptance in batches. Each batch shall consist

of the same designation, the same melting furnace number, the same

specification, the same manufacturing method, the same status, the same heat

treatment furnace batch.

5.3 Inspection items

unqualified item one by one, the qualified is group-batch again.

5.5.3 When the dimensions and allowable deviation of dimension, appearance

quality, hydraulic pressure or pneumatic pressure test of the tube are

unqualified, the single piece is judged as unqualified.

5.5.4 For tube which has an inner diameter of not more than 20 mm, it is allowed

to randomly take 5 pieces from each batch of tubes, take 150 mm tube segment

from each piece, cut into halves longitudinally. If the measured wall thickness

and the inspection of inner surface are unqualified, this batch of products is

unqualified. However, it allows for the supplier to inspect the unqualified items

one by one, the qualified is group-batch again.

6.1 Marking

The following contents shall be indicated on the tubes and packaging boxes

that have passed the inspection.

a) Product's designation;

b) Product's name;

c) Supply status;

d) Batch number;

e) This standard number.

6.2 Packaging, transport and storage

The packaging, transport and storage of the product shall comply with the

relevant provisions of GB/T 8180.

6.3 Quality certificate

Each batch of tubes shall be accompanied by a quality certificate, stating.

a) Name of supplier;

b) Name of product;

c) Designation, specification and status of product;

d) Smelting furnace number, batch number, batch weight and count;

e) Results of the various analytical tests as specified and the quality

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