Yuhong Group Co., Ltd. manufactures TEMA shell and tube heat exchangers in fixed tubesheet (BEM) and U-tube (AEU) configurations, alongside tube bundles, U-tubes, heat transfer tubes, finned tubes, tubesheets, baffles, and heads.
Wetted materials are selected independently for the shell side and the tube side against the process fluid, with carbon steel and stainless steel offered as separate choices rather than a single default.
The engineering distinction between the two configurations rests on the rear-head decision: a BEM unit fixes the bundle to both tubesheets for clean shell-side duty and a straight-tube geometry that permits mechanical tube-side cleaning, while an AEU unit uses a single tubesheet and U-bent tubes to accommodate shell-to-tube differential expansion and allow bundle withdrawal for shell-side access.
In practice, the TEMA rear-head designation tends to serve a project best when it follows the most difficult fluid and the most difficult maintenance task in the duty, rather than the lowest initial quotation.
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| A516 Gr. 70 | ASME Section VIII Div. 1 plate | −20°F to 600°F (carbon steel basis) | Non-corrosive or protected shell-side service; corrosion allowance per datasheet |
| A240 304/L | ASME Section VIII Div. 1 plate | −55°F to 600°F (stainless basis) | Mildly corrosive shell-side fluid, general chemical service |
| A240 316/L | ASME Section VIII Div. 1 plate | −55°F to 600°F (stainless basis) | Chloride-bearing or more aggressive shell-side fluid |
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| A516 Gr. 70 | ASME Section VIII Div. 1 plate | −20°F to 600°F | Carbon steel tube-side channel matched to shell material |
| A105 | ASME Section VIII Div. 1 forging | −20°F to 600°F | Nozzle and small channel forging |
| A240 304/L, 316/L | ASME Section VIII Div. 1 plate | −55°F to 600°F | Corrosive tube-side service requiring stainless wetted surface |
| A182 F304/F316 | ASME Section VIII Div. 1 forging | −55°F to 600°F | Stainless nozzle and flange forgings |
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| A516 Gr. 70 | ASME Section VIII Div. 1 plate | −20°F to 600°F | Carbon steel tubesheet, rolled or welded tube joints |
| A105 | ASME Section VIII Div. 1 forging | −20°F to 600°F | Forged tubesheet for higher thickness or small diameter |
| A240 304/L, 316/L | ASME Section VIII Div. 1 plate | −55°F to 600°F | Stainless tubesheet matched to stainless tube grade |
| A182 F304/F316 | ASME Section VIII Div. 1 forging | −55°F to 600°F | Forged stainless tubesheet for severe joint requirements |
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| A516 Gr. 70 | ASME Section VIII Div. 1 plate | −20°F to 600°F | Standard segmental baffle in carbon steel construction |
| A240 304/L, 316/L | ASME Section VIII Div. 1 plate | −55°F to 600°F | Stainless baffle where shell-side fluid requires matching material |
Baffle holes are machined 0.4–0.8 mm over tube OD to control unsupported span and flow-induced vibration risk.
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| SA179 | Seamless cold-drawn low-carbon steel tube | Commonly −29°C to 400°C, governed by ASME VIII Div. 1 allowable stress check | Low and medium-pressure heat exchanger, condenser and similar heat transfer service |
| ASTM A213 TP304/304L | Seamless austenitic stainless tube | Up to approximately 750°C published maximum service temperature | General corrosive tube-side service where corrosion resistance governs |
| ASTM A213 TP316/316L | Seamless austenitic stainless tube | Up to approximately 750°C published maximum service temperature | Chloride-bearing wet service where pitting resistance is the controlling property |
| ASTM A213 TP321 | Seamless stabilized austenitic stainless tube | Commonly 500–870°C for elevated-temperature and thermal-cycling duty | High-temperature service where titanium stabilization resists chromium carbide precipitation |
The final allowable temperature for any tube grade is established by the ASME Section VIII Div. 1 allowable-stress check at design temperature for the selected size and wall thickness, then checked against TEMA mechanical requirements for tube span, baffle spacing, and joint details.
| Grade | Specification | Temperature range | Typical service condition |
|---|---|---|---|
| A193 B7 / A194 2H | ASME bolting specification | −20°F to 600°F | Carbon steel bundle tie rods and flange bolting |
| A320 L7 / A194 Gr. 4 | ASME low-temperature bolting | Down to −101°C service range | Low-temperature duty where impact toughness is required |
| A182 F304/F316 | ASME Section VIII Div. 1 forging | −55°F to 600°F | Stainless tie rods and nozzle necks matched to wetted material |
| Parameter | Standard / typical range | Basis |
|---|---|---|
| TEMA rear-head type | BEM (fixed tubesheet) or AEU (U-tube) | TEMA designation governs bundle removability and cleaning access |
| Shell inside diameter | Up to 100 in (2,540 mm) | TEMA mechanical standards scope limit |
| Tube outside diameter | 19.05 mm (0.75 in) or 25.4 mm (1 in) standard; other TEMA sizes on request | TEMA standard tube sizes |
| Tube length | 8, 12, 16, 20, 24 ft; confirmed against plot space | Stated on the TEMA datasheet |
| Tube pitch | Not less than 1.25 × tube OD | TEMA minimum pitch ratio |
| Tube layout | 30° triangular, 60° rotated triangular, 45° rotated square, or 90° square | Triangular layouts give higher shell-side coefficient; square layouts improve mechanical cleaning access |
| Baffle hole clearance | 0.4–0.8 mm over tube OD | Controls unsupported span and vibration risk |
| Minimum baffle spacing | Greater than 0.2 × shell inside diameter | TEMA segmental baffle spacing guidance |
| Tube length-to-shell diameter ratio | Typically 5–15, with approximately 8 as a preliminary-design reference | TEMA-oriented preliminary sizing practice |
| Design temperature | Carbon steel typically −20°F to 600°F; stainless steel typically −55°F to 600°F | Project design basis; confirmed by ASME VIII Div. 1 calculation |
The exchanger is designed and fabricated to TEMA mechanical standards, with the pressure boundary constructed to ASME Section VIII Division 1 and available with ASME U Stamp when the project specification requires a code-stamped pressure vessel. Quality control scope:
NDT: radiography (RT), penetrant testing (PT), magnetic particle testing (MT), ultrasonic testing (UT), and positive material identification (PMI) as specified on the datasheet.
Tube-to-tubesheet joints: rolling, strength welding, or seal welding, selected by tube grade, tubesheet material, and fluid severity.
Material traceability: mill certificate linked to each finished component, covering shells, tubesheets, baffles, and tube stock.
Dimensional inspection: tube pitch, baffle hole clearance, tubesheet hole pattern, and bundle envelope.
Documentation: shipping marks and packing list issued against the final packing plan before dispatch.
Can a U-tube bundle be supplied as a replacement without replacing the shell?
Yes, when the existing shell, nozzles, and tubesheet bolt pattern are within TEMA dimensional tolerances.
The replacement bundle is built to the original TEMA designation and tubesheet drawing.
Tube count, pitch, and baffle spacing are verified against the datasheet before fabrication.
What is the practical difference between BEM and AEU at the procurement stage?
BEM is a fixed-tubesheet exchanger for clean shell-side service.
AEU is a U-tube exchanger with a removable bundle for thermal expansion and shell-side access.
The TEMA rear-head letter controls bundle removability and the tube-side cleaning method; the two are not substituted without re-checking the expansion and cleaning assumptions.
How is the design temperature confirmed for a specific tube grade?
The allowable temperature is taken from the ASME Section VIII Div. 1 allowable stress at design temperature for the selected material.
It is then checked against TEMA mechanical requirements for tube span, baffle spacing, and joint details.
SA179, A213 TP304/304L, TP316/316L, and TP321 each carry different governing limits, as listed in the tube table above.
What are the commercial terms?
MOQ: 1 set per configuration.
Incoterms: FOB, FCA, CIF, or EXW, quoted against the agreed destination and shipment mode.
Lead time: approximately 60–150 days after drawing approval, based on the technical requirements and design scope.
What information shortens the quotation review?
Fluid names and flow rates.
Design pressure and temperature per side.
Corrosion allowance and TEMA designation.
Tube material and length, connection sizes and facing.
NDT scope, required Incoterm, and destination port.
For datasheets, drawings, or a TEMA-based quotation, please write to vladimir@steelseamlesspipe.com
