ASME SA516 Gr.70 Heat Exchanger Baffles for Improved Heat Transfer Efficiency

Yuhong Group Co., Ltd is a leading Chinese manufacturer specializing in heat exchanger components, including tube sheets, U-tubes, heat exchanger tubes, finned tubes, baffles, covers, flanges and other related parts.

All products are manufactured strictly in accordance with customers' drawings and certified to ASME, PED, GOST and TÜV.

Baffle plate - essential component of shell-and-tube heat exchangers. Its main functions are as follows:

• Direct the flow of heat medium in the shell side (cross flow across the tube bundle)
• Increase flow turbulence and velocity to raise the heat transfer coefficient
• Support the tube bundle and reduce Flow-Induced Vibration (FIV)

These baffles are manufactured from ASME SA516 Gr.70 plate, a carbon steel for pressure vessels suitable for service at moderate and low temperatures (down to -29°C). Types: segmented baffles (single segment, double segment, NTIW, helical) with tube holes.

Normalized condition (SA516 Gr.70N) shall be adopted for plate thickness over 40 mm or where impact toughness is required.

• Direct impact on heat transfer. Segmented baffles create cross flow and eliminate dead zones. In terms of performance parameters, the shell-side flow velocity increases by 30% to 80% (depending on baffle cut), flow turbulence is enhanced, and the heat transfer coefficient is improved without enlarging the heat exchange area.
• Manufacturing precision. Laser / plasma cutting with hole positioning tolerance of ±0.2 mm. Tube holes are chamfered to minimize tube binding.
• Structural Types:
  • Single-segment baffles (baffle cut: 20–45% of shell diameter)
  • Double-segment baffles (reduced pressure drop)
  • NTIW (No Tube in Window): No tubes pass through the baffle cut area
  • Disc-and-ring baffles
  • Helical baffles: Designed for minimum flow resistance
• Size range: DN100 to DN4000 mm, plate thickness from 5 mm to 250 mm. Custom manufacturing per customer drawings (OEM).
• Additional processing: deburring, edge protection, preservation (degreasing), and anti-corrosion coating available on request.

Why choose ASME SA516 Gr.70 for shell-and-tube heat exchanger baffles?
SA516 Gr.70 delivers an optimal combination of strength (YS ≥ 260 MPa), impact toughness and weldability at a lower cost compared to stainless steels. Its operating temperature range is from -29°C to +343°C, and down to -46°C after normalizing. It is suitable for most oil, gas and chemical service conditions..

Do baffles affect tube vibration?
Yes. Baffles act as intermediate supports, and the baffle spacing determines the tube span. With proper design calculation in accordance with TEMA or ASME Section VIII, the vibration amplitude can be reduced by 3 to 5 times, preventing tube fretting wear against baffles.

Which baffle types are applied for high gas flow velocities?
For high gas flow rates or two-phase flow, double-segment baffles or helical baffles are recommended. They reduce pressure drop by 30% to 40% while maintaining the same heat transfer efficiency, compared with single-segment baffles.

Is normalizing required for SA516 Gr.70?
Per ASME SA-516 standard, normalizing is mandatory for plate thickness over 40 mm. It is also required if impact tests at temperatures below -29°C are specified, or for sour service containing hydrogen sulfide (H₂S).