Specification and allowable deviation of titanium tube and titanium alloy tube

1. The outer diameter of titanium pipe and its allowable error

The outer diameter scale and allowable error of the product remain the original national standard, which is stricter than ASTM b861-06a standard. See Table 1 and table 2 for details.

Table 1 allowable error of outer diameter in this standard

Outer diameter, mm allowable error, mm outer diameter, mm allowable error, 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 outer diameter error of ASTM b861-06a

Outer diameter, mm, allowable error, mm

3.3~38 +0.397 -0.794

>38~102±0.794

>102~203 +1.588 -0.794

2. The wall thickness of titanium pipe and its allowable error

On the basis of the original national standard, the thickness of titanium pipe was widened, and two kinds of thick wall titanium pipe with 5.0 mm and 5.5 mm were added, that is, d > 40 ~ 50 mm, t 4.0 mm, d > 50 ~ 60 mm, t 4.5 mm and 5.0 mm, d > 60 ~ 80 mm, t 5.0 mm and 5.5 mm, d > 80 ~ 110 mm, t 5.0 mm and 5.5 mm were added. The allowable error of wall thickness is the same as that of the original national standard and ASTM b861-06a standard.

3. The length of titanium pipe and its allowable error

According to the practical ability of titanium pipe production equipment and referring to GB / t3625-2007 standard, the group spacing of original outer diameter > 15mm is divided into two types: wall thickness ≤ 2.0 mm and wall thickness > 2.0 mm ~ 4.5 mm, respectively corresponding to different production length, which is more reasonable.

This standard distinguishes the allowable error of length according to the fixed length, which is slightly stricter than the original national standard.

4) Tortuosity and allowable error of titanium tube

The tortuosity of titanium pipe remains the original national standard, which is basically the same as ASTM b861-06a.

5) Out of roundness and wall thickness unevenness of titanium tube

It is completely common with the original national standard.

4. Mechanical properties of titanium pipe

Referring to the American Standard, the mechanical property objectives of TA1 and TA2 grades were revised, which were combined with the American Standard; the mechanical property targets of TA3, ta8, ta8-1, ta9-1 and TA10 titanium pipe were added, among which, the mechanical property targets of ta8, ta8-1 and ta9-1 were completely the same with the corresponding brands of American Standard, and the tensile strength of TA3 was higher than that of American Standard; the tensile strength of TA10 titanium pipe was improved compared with the national standard After revision, the tensile strength and yield strength of TA10 are slightly lower than those of American Standard; the tensile strength target of ta9 is slightly higher than that of American Standard and original national standard. The comparison of mechanical properties between this standard and the original national standard and ASTM b861-06a is shown in the attached table.

5. Process performance of titanium pipe

The target of TA3 and ta9-1 process performance check was added;

Based on the original GB / t3624-1995, the bending test requirements of titanium pipe are added. The tortuous target is the same as ASTM b861-06a, and the demander can select and carry out according to the demand;

On the basis of the original national standard, the pressure value of TA10 hydraulic test is adjusted (the rule of s value of TA10 titanium pipe hydraulic test in the original GB / t3624-1995 is changed from 40% of tensile strength to 50% of the minimum value of corresponding rule non share elongation strength); and the hydrostatic test objectives of ta8, ta8-1 and ta9-1 are regulated. All the grades in this standard have the same objectives as the corresponding grades in ASTM b861-06a.

According to ASTM b861-06a, titanium tubes are divided into two grades: less than or equal to 25.4mm and greater than 25.4mm according to the outer diameter value. The values of E are 0.04 and 0.06 respectively, which is more scientific for checking. The flattening targets in this standard are the same as ASTM b861-06a (ASTM b861-06a does not make rules for flattening experiments of Gr12 and gr17, and this standard also refers to other brands to make rules for corresponding brands), and refer to ASTM together According to b861-06a standard, the rule that "when flattening test is carried out on titanium pipe with D / T < 10, the crack on the inner surface of titanium pipe corresponding to" 6 o'clock "and" 12 o'clock "shall not be regarded as the basis for rejection" is added to the original national standard.

In view of the practical use demand in China, the water pressure (or air pressure), flattening and tortuous test rules can be carried out when the demander requires them and it is indicated in the contract, that is, it is common with the original GB / t3624-1995.