JIS G3462 STBA12 Alloy Steel Seamless Boiler Tubes
JIS G3462 STBA12 Alloy Steel Tubes are mainly used for exchanging heat on within and in the vicinity of the underground. It can use as water tube, smoke tube, superheated tubes, air preheater tube, etc.
Description
JIS G3462 STBA12 Alloy Steel Boiler Tubes
Standard: JIS G3462
Alloy steel boiler and heat exchanger tubes
JIS G3462 STBA12 Alloy Steel Tubes are mainly used for exchanging heat on within and in the vicinity of the underground. It can use as water tube, smoke tube, superheated tubes, air preheater tube, etc.
JIS G3462 STBA12 alloy steel tube is not applicable for heating furnaces and heat exchangers for low temperature service.
JIS G3462 STBA12 Alloy steel boiler and heat exchanger tubes Quick Details
Type:Seamless or electric resistance welding.
Wall thickness(WT): 3.2mm——14 mm.
Outer diameter (OD): 19.05mm——168.3 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Treaded
FOB Price: US $1000-2000 / Ton | 1 Ton/Tons (Min. Order)
Method of Manufacture
The tubes of STBA 12 shall be manufactured by seamless process or by electric resistance welding process
The tube shall be subjected to heat treatments
| grade | Heat treatment |
| STBA 12 | Low temperature annealing, isothermal annealing, full annealing, normalizing or normalizing followed by tempering |
Remark
Low temperature annealing shall not be applied to the electric resistance welded steel tube.
Chemical Composition
| Standard | Grade | Chemical Composition Limits (%) | ||||||
| C | Si | Mn | P | S | Cr | Mo | ||
| JIS G3462 | STBA12 | 0.10-0.20 | 0.10-0.50 | 0.30-0.80 | ≤ 0.035 | ≤ 0.035 | – | 0.45-0.65 |
Mechanical Properties
| Grade | Tensile Property (N/mm2) | Yield Point or Yield Strength (N/mm2) | Elongation (%) | ||
| OD ≥ 20 mm | 10 mm ≤ OD ＜20 mm | OD ＜10 mm | |||
| NO. 11 Sample; NO. 12 Sample | NO. 11 Sample | NO. 11 Sample | |||
| Longitudinal | Transverse | Transverse | |||
| STBA12 | ≥ 382 | ≥ 206 | ≥ 30 | ≥ 25 | ≥ 22 |
Note:
1. The above table is only applicable for heat exchanger alloy steel pipes. The buyer can appoint the upper limit value of tensile strength. The upper limit value of tensile strength is the above shown value plus 147 N/mm2.
2. For the alloy steel tube with the thickness of less than 8 mm, we use NO.12 sample for tensile test. The minimum elongation will be reduced by 1.5% from the table value when the thickness reduces 1 mm. The value obtained will be rounded to an integer value according to JIS Z 8401 (a rounding method).
3. When we take the electric resistance welded steel pipes for tensile test, we also choose NO.12 sample from the parts not containing welding seams.
Unit mass of tube
W=0.2466 t (D-t)
where
W: unit mass of tube(kg/m)
t: wall thickness of tube(mm)
D: outside diameter of tube(mm)
The dimensional tolerances of tube shall be as follows:
(1)The tolerance on the outside diameter of the tube
Tolerances on Outside Diameter Unit: mm
| Division of outside diameter | Tolerances on outside diamete | |||
| Hot finished seamless steel tube | Cold finished seamless steel tube | Electric resistance welded steel tube other than cold finished | Cold finished electric resistance welded steel tube | |
| Under 25 | +0.4
-0.8 |
【0.10 | 【1.5 | 【0.10 |
| 25 or over to and excl. 40 | 【0.15 | 【0.20 | 【0.15 | |
| 40or over to and excl. 50 | 【0.20 | 【0.25 | 【0.20 | |
| 50 or over to and excl 60 | 【0.25 | 【0.30 | 【0.25 | |
| 60 or over to and excl. 80 | 【0.30 | 【0.40 | 【0.30 | |
| 80 or over to and excl. 100 | 【0.40 | +0.40 | 【0.40 | |
| -0.60 | ||||
| 100 or over to and excl.12 | +0.4
-1.2 |
+0.40 -0.60 |
+0.40 -0.80 |
+0.40 |
| -0.60 | ||||
| 120 or over to and excl.160 | +0.40 -0.80 |
+0.40 -1.00 |
+0.40 | |
| -0.80 | ||||
| 160 or over to and excl.200 | +0.4 | +0.40 | +0.40 | +0.40 |
| -1.8 | -1.20 | -1.20 | -1.20 | |
| 200 or over | +0.4 | +0.40 | +0.40 | +0.40 |
| -2.4 | -1.60 | -1.60 | -1.60 | |
Note:For the tolerances on the outside diameter of electric resistance welded steel tube other than cold finished, if specially required by the purchaser, the tolerances on the outside diameter of cold finished steel tube may substitute.
(2)Tolerances on Wall Thickness and on Thickness Deviation
| Tolerances | Division of wall thickness (mm) |
Division of method of manufacture | Hot finished seamless steel tube | Cold finished seamless steel tube | Electric resistance welded steel tube | |||
| Division of outside diameter (mm) | Under 100 | 100 or over | Under 40 | 40 or over | Under 40 | 40 or over | ||
| Tolerances on wall thickness % | Under 2 | — | — | +0.4mm | +22
0 |
+0.3 | +18
0 |
|
| 0 | 0 | |||||||
| 2 or over to and excl. 2.4 | +40 | — | +20
0 |
+18
0 |
||||
| 0 | ||||||||
| 2.4 or over to or excl. 3.8 | +35 | +35 | ||||||
| 0 | 0 | |||||||
| 3.8 or over to or excl. 4.6 | +33 | +33 | ||||||
| 0 | 0 | |||||||
| 4.6 or over | +28 | +28 | ||||||
| 0 | 0 | |||||||
| Tolerances on thickness disparity % |
— | Within 22.8 of wall thickness | — | — | ||||
Note:The “thickness deviation” means the ratio of the difference between the maximum and the minimum thickness of the wall measured in the same section to the ordered wall thickness and shall not be applied to the tube under 5.6 mm in wall thickness
(3)The Tolerance on length of the tube
| Division | Tolerance on length | ||
|
50 mm or under in
outside diameter
|
7 m or under in length | +0.7 mm | |
| 0 | |||
| Over 7 m in length |
Add 3 mm to the plus side permissible deviation given above for each increase of 3m or its fraction in length. However, the maximum value shall be 15 mm.
|
||
|
Over 50 mm in
outside diameter
|
7 m or under in length | +10mm | |
| 0 | |||
| Over 7 m in length |
Add 3 mm to the plus side permissible deviation given above for each increase of 3m or its fraction in length. However, the maximum value shall be 15mm.
|
||
Note:When accurate length is particularly required, the tolerances on it shall be agreed upon by the purchaser and the manufacturer.