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ASTM A688 tube
What is ASTM A688?
The ASTM A688 is a standard specification for feedwater heater ss tubes in seamless and welded variants. All the finished straight ASTM A688 Tube ready for U-bending need to be solution-annealed. The annealing procedure would consist of heating the material to a minimum temperature of 1040 °C, and then they should be rapidly cooled below 370 degrees C. It is crucial to determine the corrosion resistance properties of each sample ASTM A688 Welded Tube. A688 is available in different grades and can be found in superheaters, heat exchangers, etc.
ASTM A688 TP304L seamless tube manufacturer in India
ASTM A688 TP304L vs TP316L
The primary difference between ASTM A688 TP304L and TP316L lies in their chemical composition. The ASTM A688 TP304L material has a greater chromium content than the TP316L material. However, it has a lower nickel content. The ASTM A688 TP316LN Boiler Tubes have added molybdenum in their alloy, which enhances its chemical resistance properties. Talking about the mechanical properties, it is quite similar, as both of them have the same hardness, tensile strength, and yield strength.
Supplier Of ASTM A688 seamless tube and A688 Class K stainless steel feedwater heater tubes In Gujarat as per ASME SA688 standards
ASTM A688 tube
ASTM A688 TP304L tube
ASTM A688 seamless tube
Which is the most common method to manufacture ASTM A688 seamless tube?
The extrusion process is the most common method for manufacturing ASTM A688 seamless tube. This is basically a comprehensive deformation process, wherein the metal is squeezed through an orifice or die opening so as to obtain a reduction in the diameter. This leads to an increase in the metal block. Through the procedure, one can get the desired cross-section on their seamless ASTM A688 TP316LN Boiler Tubes.
We have ASTM A688 Welded Tube and U-tubes from 12mm to 102mm in outer diameter in stock, check A688M coil tubing specification
Table of Contents
- Specifications of ASTM A688 TP304L tube
- ASTM A688 tube types
- A688 stainless steel feedwater heater tubes equivalent
- Mechanical properties of A688 u-tubes
- ASTM A688 welded tube testing
- ASTM A688 TP316LN boiler tubes tolerance
- Chemical composition of ASTM A688 grade TP304LN material
- ASTM A688 seamless tube dimensions
- ASTM A688 tube heat treatment
Specifications of ASTM A688 TP304L tube
| O.D | Wall Thickness | Length |
|---|---|---|
| 12.7 – 102 MM | 0.5 – 5 MM | Straight Lenghts upto 30 meters |
| Schedule | Welding Method | Bending radius |
| SCH. 5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, XXS | Plasma or Laser | max 1500 mm |
| Manufacturing method | Testing |
Application |
| cold drawing, cold worked |
|
Boiler,Heat Exchanger, Cooling, Condenser , Heater |
Stockist of A688 TP316LN boiler tubes and ASTM A688 Grade TP304LN material in coiled, round and u bend design
ASTM A688 tube types
ASTM A688 welded tube
A688 stainless steel feedwater heater tubes
A688 u-tubes
ASTM A688 TP316LN boiler tubes
ASTM A688 grade TP304LN material
ASTM A688M coil tubing
ASTM A688 TP316N heater tubes
ASTM A688 Class D condenser tube
A688 Class K bright annealed tubes
A688 Class F heat exchanger tubes
ASTM A688 Class C cold drawn seamless tube
A688 Class B tubing
Stockist of ASTM A688 TP316N heater tubes in various surface finish, check A688 Class D condenser tube chemical properties
A688 stainless steel feedwater heater tubes equivalent
| GRADE | DIN/WERKSTOFF | UNS NO |
|---|---|---|
| ASTM A688 304 | 1.4301 | S30400 |
| A688 304H | – | S30409 |
| ASTM A688 304L | 1.4306 | S30403 |
| A688 310S | 1.4845 | S31008 |
| ASTM A688 316S | 1.4436 | S31600 |
| A688 316H | – | S31609 |
| ASTM A688 316 TI | 1.4571 | S31635 |
| A688 316L (2.5 MIN MOLY) | 1.4435 | S31603 |
| ASTM A688 316L | 1.4404 | S31603 |
| A688 317L | 1.4438 | S31703 |
| ASTM A688 321 | 1.4541 | S32100 |
| A688 321H | – | S32109 |
| ASTM A688 347 | 1.4550 | S34700 |
| Element | Classes G to N and GH to NH | Classes A to F and AH to FH |
|---|---|---|
| Manganese % maximum | - | 1.35 |
| Phosphorous % maximum | 0.040 | 0.050 |
| Sulfur % maximum | 0.040 | 0.050 |
Mechanical properties of A688 u-tubes
| Grade and UNS | Yield strength minimum ksi [Mpa] | Tensile strength minimum ksi [Mpa] | Elongation in 2in or 50mm minimum % | ||||||
| 304, 316 S30400, S31600 | 30 [205] | 75 [515] | 35 | ||||||
| 304L, 316L S30403, S31603 | 25 [175] | 70 [485] | 35 | ||||||
| XM-29 S24000 | 55 [380] | 100 [690] | 35 | ||||||
| 304N, 316N S30451, S31651 | 35 [240] | 80 [550] | 20 | ||||||
| 304LN, 316LN S30453, S31653 | 30 [205] | 75 [515] | 35 | ||||||
| N08367 t≤0.187 | 45 [310] | 100 [690] | 30 | ||||||
| N08367 t＞0.187 | 45 [310] | 95 [655] | 30 | ||||||
| N08926 | 45 [310] | 94 [650] | 35 | ||||||
| S31254t≤0.187 | 45 [310] | 100 [690] | 35 | ||||||
| S21254t＞0.187 | 45 [310] | 95 [655] | 35 | ||||||
| S32654 | 65 [450] | 120 [825] | 40 | ||||||
ASTM A688 welded tube testing
- Tensile Strength
- Reverse bending test
- Flattening test
- Flare test
- Flange test
- Dimensional
- Hydrostatic Test
- Pneumatic Test
- Hardness
- Eddy Current test
- Intergranular Corrosion (option)
ASTM A688 TP316LN boiler tubes tolerance
| Acceptable Description | Tolerances |
|---|---|
| Leg Lengths Different | ≤ 3.2 Milimeter |
| Deviation From Plane Of Bend | ≤ 1.5 Milimeter |
| Leg Lengths Tolerance L L ≤ 6 M 6 > L ≤ 9 M L > 9 M | +3.2 Milimeter – 0 +4 Milimeter – 0 +4.8 Milimeter – 0 |
| Leg Spacing (Measured At Tangency Point) | ± 1.5 Milimeter |
| Radius R | ± 1.5 Milimeter |
| Wall Thickness In Bent Portion | Shall Not Be Less Than The Value Determined By The below Equation: Tf = (4R X T) / (4R + D) Where : Tf = Wall Thickness After Bending T = minimum Wall Thickness Before Bending R = Centerline Bend Radius D = No minimal Outside Tube Dia |
| Ovality In The Bent Portion (Also Called Flattening) | ± 10 % This Can Be Described As Follow. (D maximum – D) / D < 10% (D – D minimum) / D < 10% “Neither The Major Nor minimum or Dia Of The Tube Shall Deviate From The No minimal Dia Prior To Bending By More Than 10%” |
| Squareness Of Ends D ≤ 15.9 Milimeter 15.9 > D ≤ 25.4 D ≥ 25.4 ≤ 38.1 | 0.25 Milimeter 0.4 Milimeter 0.4 Milimeter |
Chemical composition of ASTM A688 grade TP304LN material
| Grade | TP 304L | TP 304 | TP 316 | TP 316L | TP 316N | . . . | . . . | TP 316LN | TP 304LN | TP 304N | TP XM-29 | . . . | . . . | |
| Element | UNS | S30403 | S30400 | S31600 | S31603 | S31651 | N08367 | N08926 | S31653 | S30453 | S30451 | S24000 | S31254 | S32654 |
| Composition, % | ||||||||||||||
| Carbon, maximum | 0.035 | 0.08 | 0.08 | 0.035 | 0.08 | 0.030 | 0.020 | 0.035 | 0.035 | 0.08 | 0.060 | 0.020 | 0.020 | |
| Manganese, maximumB | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 2.00 | 11.50– | 1.00 | 2.0–4.0 | |
| 14.50 | ||||||||||||||
| Nickel | 8.00– | 8.00– | 10.00– | 10.00– | 10.00– | 23.50– | 24.00– | 10.00– | 8.00– | 8.00– | 2.25– | 17.5– | 21.0– | |
| 13.00 | 11.00 | 14.00 | 15.00 | 14.00 | 25.50 | 26.00 | 15.00 | 13.00 | 11.0 | 3.75 | 18.5 | 23.0 | ||
| Chromium | 18.00– | 18.00– | 16.00– | 16.00– | 16.0– | 20.00– | 19.00– | 16.00– | 18.00– | 18.0– | 17.00– | 19.5– | 24.0– | |
| 20.00 | 20.00 | 18.00 | 18.00 | 18.0 | 22.00 | 21.00 | 18.00 | 20.00 | 20.0 | 19.00 | 20.5 | 25.0 | ||
| Molybdenum | … | … | 2.00– | 2.00– | 2.00– | 6.00– | 6.0– | 2.00– | … | … | … | 6.0– | 7.0– | |
| 3.00 | 3.00 | 3.00 | 7.00 | 7.0 | 3.00 | 6.5 | 8.0 | |||||||
| Phosphorus, maximum | 0.040 | 0.040 | 0.040 | 0.040 | 0.040 | 0.040 | 0.03 | 0.040 | 0.040 | 0.040 | 0.060 | 0.030 | 0.030 | |
| Sulfur, maximum | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.030 | 0.01 | 0.030 | 0.030 | 0.030 | 0.030 | 0.010 | 0.005 | |
| Silicon, maximum | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 1.00 | 0.5 | 0.75 | 0.75 | 0.75 | 1.00 | 0.80 | 0.50 | |
| NitrogenC | … | … | … | … | 0.10– | 0.18– | 0.15– | 0.10– | 0.10– | 0.10– | 0.20– | 0.18– | 0.45– | |
| 0.16 | 0.25 | 0.25 | 0.16 | 0.16 | 0.16 | 0.40 | 0.22 | 0.55 | ||||||
| Copper | . . . | . . . | . . . | . . . | . . . | 0.75 maximum | 0.5–1.5 | . . . | . . . | . . . | . . . | 0.50–1.00 | 0.30–0.60 |
ASTM A688 seamless tube dimensions
| Group | Permissible Variations in Outside Diameter, in.[milimeter] | Size, Outside Diameter, in(milimeter) | Permissible Variations in WT, % | PermisibleVariations
in Cut Length, in[milimeter]Over Under |
|
| ASTM A688 SS welded tube 1 | ±0.005[0.13] | Up to 1/2(12.7), excl | ±15 | 1/8[3] | 0 |
| ASTM A688 stainless steel welded tube 2 | ±0.005[0.13] | 1/2 to 1 1/2(12.7 to 38.1 excl | ±10 | 1/8[3] | 0 |
| ASTM A688 welded tube 3 | ±0.010[0.25] | 1 1/2 to 3 1/2(38.1 to 88.9 excl | ±10 | 3/16[5] | 0 |
| A688 stainless steel welded tube 4 | ±0.015[0.38] | 3 1/2 to 5 1/2(88.9 to 139.7 excl | ±10 | 3/16[5] | 0 |
| ASTM A688 welded tube 5 | ±0.030[0.76] | 5 1/2 to 5 1/2(139.7 to 230.2 excl | ±10 | 3/16[5] | 0 |
Difference between ASTM A688 Class D, A, B, E & F
The difference between A688 stainless steel feedwater heater tubes Class D, A, B, E & F is in their mechanical requirements. They have different levels of tensile strength, yield strength, elongation, and hardness level for different sizes.
They undergo different heat treatments. Grade A is generally untreated whereas grades B, C & D undergo annealing /normalization/ normalization and tempering. Grade E is either normalized and tempered or double normalized and tempered. Whereas Grade F is quenched and tempered or normalized.
ASTM A688 mechanical properties
| Class | Size, inches | Yield, min ksi | Tensile, min ksi | RA, % min | Elong, % min in 2” | Hardness, HBN |
|---|---|---|---|---|---|---|
| A | Up to 20 | - | 47 | - | - | 183 max |
| B | Up to 20 | 30 | 60 | 36 | 24 | 120-174 |
| C | Up to 12 | 33 | 66 | 36 | 23 | 137-183 |
| 12 to 20 | 33 | 66 | 34 | 22 | 137-183 | |
| D | Up to 8 | 37.5 | 75 | 40 | 24 | 149-207 |
| 8 to 12 | 37.5 | 75 | 35 | 22 | 149-207 | |
| 12 to 20 | 37.5 | 75 | 19 | 20 | 149-207 | |
| Over 20 | 37.5 | 75 | 30 | 19 | 149-207 | |
| E | Up to 8 | 44 | 85 | 40 | 25 | 174-217 |
| 8 to 12 | 44 | 85 | 37 | 23 | 174-217 | |
| 12 to 20 | 43 | 83 | 35 | 22 | 174-217 | |
| F | Up to 4 | 55 | 90 | 39 | 20 | 187-235 |
| 4 to 7 | 50 | 85 | 39 | 20 | 174-217 | |
| 7 to 10 | 50 | 85 | 37 | 19 | 174-217 | |
| 10 to 20 | 48 | 82 | 36 | 19 | 174-217 | |
| G | Up to 12 | 50 | 80 | 40 | 24 | 163-207 |
| 12 to 20 | 50 | 80 | 38 | 22 | 163-207 | |
| H | Up to 7 | 60 | 90 | 44 | 22 | 187-235 |
| 7 to 10 | 58 | 90 | 42 | 21 | 187-235 | |
| 10 to 20 | 58 | 90 | 40 | 18 | 187-235 | |
| J | Up to 7 | 70 | 95 | 50 | 20 | 197-255 |
| 7 to 10 | 65 | 90 | 50 | 20 | 187-235 | |
| 10 to 20 | 65 | 90 | 48 | 18 | 207-255 | |
| K | Up to 7 | 80 | 105 | 50 | 20 | 212-269 |
| 7 to 10 | 75 | 100 | 50 | 19 | 207-269 | |
| 10 to 20 | 75 | 100 | 48 | 18 | 207-269 | |
| L | Up to 4 | 105 | 125 | 50 | 16 | 255-321 |
| 4 to 7 | 95 | 115 | 45 | 16 | 235-302 | |
| 7 to 10 | 85 | 110 | 45 | 16 | 223-293 | |
| 10 to 20 | 85 | 110 | 40 | 14 | 223-293 | |
| M | Up to 4 | 120 | 145 | 45 | 15 | 293-352 |
| 4 to 7 | 115 | 140 | 40 | 14 | 285-341 | |
| 7 to 10 | 110 | 135 | 40 | 13 | 269-331 | |
| 10 to 20 | 110 | 135 | 38 | 12 | 269-341 | |
| N | Up to 4 | 140 | 170 | 40 | 13 | 331-401 |
| 4 to 7 | 135 | 165 | 35 | 12 | 331-401 | |
| 7 to 10 | 130 | 160 | 35 | 11 | 321-388 | |
| 10 to 20 | 130 | 160 | 35 | 11 | 321-402 |
ASTM A688 tube heat treatment
| Class | Heat Treatment |
|---|---|
| A | Untreated |
| B | Annealed, or normalized, or normalized and tempered |
| C | Annealed, or normalized, or normalized and tempered |
| D | Annealed, or normalized, or normalized and tempered |
| E | Normalized and tempered or double normalized and tempered |
| F | Quenched and tempered, or normalized, quenched and tempered |
| G | Annealed, or normalized, or normalized and tempered |
| H | Normalized and tempered |
| J | Normalized and tempered, or normalized, quenched and tempered |
| K | Normalized, quenched and tempered |
| L | Normalized, quenched and tempered |
| M | Normalized, quenched and tempered |
| N | Normalized, quenched and tempered |