1. The outer diameter of titanium pipe and its allowable deviation
The outer diameter range and allowable deviation of the production can be maintained in the original national standard without change. It is stricter than the ASTM B861-06a standard. See Table 1 and Table 2 for details.
Table 1 The allowable deviation of the outer diameter specified in this standard
Outer diameter, mm allowable deviation, mm outer diameter, mm allowable deviation, mm
3 ~ 10 ± 0.15> 50 ~ 80 ± 0.65
> 10 ~ 30 ± 0.30> 80 ~ 100 ± 0.75
> 30 ~ 50 ± 0.50> 100 ± 0.85
Table 2 Allowable deviation of outer diameter specified by ASTM B861-06a
Outer diameter, mm allowable deviation, mm
3.3 ~ 38 +0.397 -0.794
> 38 ~ 102 ± 0.794
> 102 ~ 203 +1.588 -0.794
2. Wall thickness of titanium pipe and its allowable deviation
On the basis of the original national standard, the production thickness of titanium tubes has been expanded, and thick-wall titanium tubes of two specifications of 5.0mm and 5.5mm have been added, that is, compared with the original national standard, D> 40 ~ 50mm, t 4.0mm, D> 50 ~ 60mm, t 4.5mm and 5.0mm, D> 60 ~ 80mm, t 5.0mm and 5.5mm, D> 80 ~ 110mm, t 5.0mm and 5.5mm thick wall specifications. The allowable deviation of the wall thickness is equivalent to the original national standard and is completely consistent with the ASTM B861-06a standard.
3. Length of titanium pipe and its allowable deviation
According to the actual capacity of titanium tube production equipment, referring to the GB / T3625-2007 standard, the group distance of the original outer diameter> 15mm is divided into two categories of wall thickness ≤ 2.0mm and wall thickness> 2.0mm ~ 4.5 mm, respectively corresponding to different The length can be produced, which is more reasonable.
This standard divides the length allowable deviation according to the fixed length, which is slightly stricter than the original national standard.
4) The bending degree of titanium pipe and its allowable deviation
The bending degree of the titanium pipe material maintains the original national standard index requirements, which is basically equivalent to ASTM B861-06a.
5) Unevenness and uneven wall thickness of titanium pipes
Is completely consistent with the original national standard.

4. Mechanical properties of titanium pipes
The mechanical performance indexes of the original national standard TA1 and TA2 grades were revised with reference to the American standard, and the revised version was consistent with the American standard; TA3, TA8, TA8-1, TA9-1 mechanical performance indexes and TA10 titanium tube yield strength indexes were added The mechanical properties of TA8, TA8-1, and TA9-1 are completely consistent with the corresponding grades of the American standard. The tensile strength of TA3 is higher than that of the American standard; the tensile strength index of TA10 titanium pipe is improved compared with the national standard. The index is slightly lower than the American standard; the TA9 tensile strength index is slightly higher than the American standard and the original national standard. See the attached table for the comparison of the mechanical properties of this standard with the original national standard and ASTM B861-06a.

5. Process performance of titanium pipe
Added TA3, TA9-1 process performance evaluation indicators;
In addition to the original GB / T3624-1995, the requirements of titanium tube bending test are added, the bending index is consistent with ASTM B861-06a, and the purchaser can choose to carry out according to the needs;
Adjusted the pressure value of the TA10 hydraulic test on the basis of the original national standard. 50% of the minimum value); and specifies the hydraulic test index of TA8, TA8-1, TA9-1 brands. The hydraulic test indexes of all grades in this standard are consistent with the corresponding grades in ASTM B861-06a.
The value of e in the calculation formula of the platen spacing H of the original national standard flattening test was adjusted appropriately, that is, the titanium pipe was divided into two grades of less than or equal to 25.4mm and more than 25.4mm according to the outer diameter value according to the ASTM B861-06a standard. The values ​​of e are 0.04 and 0.06 respectively, so that the assessment is more disciplined. The flattening index specified in this standard is consistent with ASTM B861-06a (ASTM B861-06a does not specify the flattening test for Gr12 and Gr17, and this standard also refers to other grades for their corresponding grades), and also refers to ASTM The B861-06a standard stipulates that when a flattening test is performed on a titanium pipe with D / t <10, the inner surface of the titanium pipe is equivalent to “6 o’clock” and “12 o’clock” The cracks should not be used as the basis for rejection “.