GB/T 38973-2020Titanium and titanium alloy bars for additive manufactural powder (English PDF)

3.1 Product classification

The designation, status and specifications of the bars shall meet the requirements of Table 1. Other specifications, if any, shall be indicated in the order form (or contract).

3.3 Dimensions and allowable deviation

3.3.1 The allowable deviation of bar diameter is ±0.1 mm.

3.3.2 The allowable deviation of bar length is ±5 mm. A small number of bars whose length is shorter than the nominal length of 10 mm ~ 100 mm is allowed; the number shall not exceed 5% of the total number.

3.3.3 Both ends of the bar shall be cut flat; the cut slope shall not be greater than 4 mm.

3.3.4 The straightness of the bar shall not be greater than 2 mm/m. When the buyer has special requirements for straightness, it shall be indicated in the order form (or contract).

3.4 Ultrasonic inspection

Bars shall be subjected to ultrasonic inspection, which shall meet the requirements of Grade A in GB/T 5193; there shall be no defects such as internal cracks and inclusions.

3.5 Surface condition

The bars are supplied with a machined surface; the surface roughness Ra value shall not be greater than 3.2 µm.

3.6 Appearance quality

3.6.1 The surface of the bar shall be clean; no defects such as oxide scale, cracks, and folds are allowed. Local defects on the surface of the bar shall be removed; the cleaning depth shall not exceed the allowable deviation of the diameter.

3.6.2 The surface of the bar is allowed to have individual minor scratches, indentations, pitting and other defects that are not more than half of the allowable deviation of the diameter.

5.4 Determination of the test result

5.4.1 When the chemical composition test result is unqualified, a repeated test is allowed for the unqualified element. If repeated inspections are still unqualified, judge the batch of products as unqualified.

5.4.2 When the external dimensions and allowable deviations, ultrasonic inspection, surface condition, and appearance quality inspection results are unqualified, judge a single piece as unqualified.

6.1 Product marking

The end face of each bar shall be marked with the following:

a) designation;

b) specifications;

c) status;

d) smelting furnace number or batch number.

6.2 Packaging, marking, transportation and storage

The packaging, marking, transportation and storage of bars shall meet the requirements of GB/T 8180.

6.3 Quality certificate

Each batch of bars shall be accompanied by a quality certificate, indicating:

a) name of the supplier; […]