ASTM A249 TP304 Bright Annealed Stainless Steel Welded Tube for Superheater
ASTM A249 TP304 Bright Annealed Stainless Steel Welded Tube for Superheater
Bright annealing tube under a reducing atmosphere or in a vacuum protection, after high temperature solid melting and rapid cooling to get the stainless steel tube, requiring the inner surface has a very good surface roughness and cleanliness, is a comprehensive consideration of organizational stability corrosion resistance and workability of the pipe.
ASTM A249 TP304 Stainless Steel Tube Specifications
- Welded : A249, A269, A789, EN10217-7
- Seamless: A213, A269, A789
- Grade: 304, 304L, 316, 316L, 321, 2205
- Finishing: Bright annealing
Difference Between Seamless And Welded Tube & Pipe
Seamless and welded are mainly two types stainless steel tube & stainless steel pipe, there is a debate whether seamless is better than welded for a long time. Although with improved metallurgy and welding processes in welded tubes, the arguments typically focus on structural integrity and corrosion resistance in weld area.
ASTM A249 TP304 Chemical Composition
| Grade | C | Si | Mn | Cr | Ni | S | P | Fe |
| TP304 | 0,08 | 1,0 | 2 | 18 – 20 | 8 – 11 | 0,03 | 0,045 | Bal. |
ASTM A249 TP304 Mechanical Properties
| Grade | Tensile Strength (Mpa) | Yield Point (Mpa) | Elongation (%) |
| TP304 | 515 | 205 | 35 |
Dimensional Tolerences
all dimensions in inches (mm)
| Size OD | Nominal Wall | Outside Diameter | Length | Wall |
| 1/2" (12.7) | 0.065" (1.65)/0.049" (1.25) | +/-0.005 (0.13) | +1/8" (3.18) - 0 | +/-10.0% |
| 3/4" (19.1) | 0.065" (1.65)/0.049" (1.25) | +/-0.005 (0.13) | +1/8" (3.18) - 0 | +/-10.0% |
| 1" (25.4) | 0.065" (1.65)/0.049" (1.25) | +/-0.005 (0.13) | +1/8" (3.18) - 0 | +/-10.0% |
| 1-1/2" (38.1) | 0.065" (1.65)/0.049" (1.25) | +/-0.008" (0.20) | +1/8" (3.18) - 0 | +/-10.0% |
| 2" (50.8) | 0.065" (1.65)/0.049" (1.25) | +/-0.008" (0.20) | +1/8" (3.18) - 0 | +/-10.0% |
| 2-1/2" (63.5) | 0.065" (1.65) | +/-0.010" (0.25) | +1/8" (3.18) - 0 | +/-10.0% |
| 3" (76.2) | 0.065" (1.65) | +/-0.010" (0.25) | +1/8" (3.18) - 0 | +/-10.0% |
| 4" (101.6) | 0.083" (2.11) | +/-0.015" (0.38) | +1/8" (3.18) - 0 | +/-10.0% |
| 6" (152.4) | 0.083" (2.11) | +/-0.030" (0.76) | +1" (25.4) - 0 | +/-10.0% |
| 6" (152.4) | 0.109" (2.77) | +/-0.030" (0.76) | +1" (25.4) - 0 | +/-10.0% |
| 8" (203.2) | 0.109" (2.77) | +0.061" (1.55)/-0.031" (0.79) | +1" (25.4) - 0 | +/-10.0% |
Cold Working
After welding, inside and outside of tube most be forged to achieve high integrity, then have a correct properties, and also possess precise dimensions.
Heat Treatment
Annealing is a very important process, tubes are heated to required solution temperature and rapidly cooling, ASTM A249 TP304 stainless steel requires minimum solution temperature is 1040 degree, it can restabilize microstructure to ensure premium properties.
Bright Annealing Option
Bright annealing welded tube is often required, tube pass through in closed furnace, inserting hydrogen gas to isolate surrounding atmosphere, finally forming a passive oxide film on the surface.
Quality Control System
Tube analysis shall conform to the requirements as to chemical composition specified on ASTM A249 TP304 grade, usually we use PMI method to identify the material.
Nondestructive Testing
In practice, eddy current tests perform well in the most case, to detect tube imperfection. Each tube is inspected by ECT.
Dimensional Inspection
All the tubes should be meet to requirements of ASTM A249 specification, including tolerance of the tube outside diameter (OD), wall thickness, and length, minimum wall thickness tube is available.
Applications
Bright annealed stainless steel welded pipe is widely used in making military products, semiconductor, biological medicine, precision instruments and meters, hydraulic parts and many other industrial products.
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