In the boiler manufacturing industry, structural integrity under pressure and thermal stress is non-negotiable. Whether fabricating fire-tube boilers, water-tube units, economizers, superheaters, or pressure drums, stress relief heat treatment is a crucial step to ensure durability, dimensional stability, and compliance with design codes like ASME Section I, Indian Boiler Regulations (IBR), and EN 12952. At Maan Global Industries, we engineer custom stress relief furnaces for boiler manufacturers to meet the industry’s high-temperature stress-relieving demands. Our systems are designed for large shell diameters, heavy wall thicknesses, and long welded seams, making us a trusted partner for both domestic and international boiler plants.
Post Weld Heat Treatment Furnace Manufacturer
Why Is Stress Relief Necessary in Boiler Manufacturing?
Table of Contents
Welding during the fabrication of boiler shells, headers, and steam drums introduces high levels of residual stress due to rapid heating and cooling cycles. This residual stress can lead to:
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Distortion and warping of boiler shells during further assembly
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Crack initiation in weld zones, especially under cyclic pressure/temperature
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Reduced fatigue life, especially in high-temperature/high-pressure boilers
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Failure to meet regulatory inspection (NDT, hydro tests, or PWHT certification)
Stress relief furnaces for boiler manufacturers help mitigate these issues by reheating the welded component to a subcritical temperature—typically between 580°C and 700°C—to allow internal stresses to redistribute and relax without changing the material’s microstructure.
Tempering Furnace Manufacturer
Roller Hearth Furnace Manufacturers
Key Benefits of Stress Relief in Boilers
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Removes harmful tensile stresses from weld zones
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Improves toughness and ductility in heat-affected zones (HAZ)
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Ensures structural dimensional stability
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Enhances long-term service performance under pressure and thermal cycling
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Enables compliance with ASME PWHT charts and IBR norms
Post-weld heat treatment (PWHT) is mandatory for boiler drums and high-pressure parts above certain thicknesses (e.g., >20mm), especially in carbon and alloy steels.
Types of Stress Relief Furnaces for Boiler Fabrication
At Maan Global, we supply a wide range of stress relief furnace configurations designed for the geometry, volume, and handling needs of boiler manufacturing.
1. Bogie Hearth Stress Relief Furnace
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Description: A walk-in type furnace with a mobile trolley (bogie) that rolls in and out for loading heavy boiler parts.
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Applications: Large boiler shells, steam drums, complete assembled bodies.
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Heating Options: Gas fired or electric Furnace.
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Benefits: High load capacity, uniform heating, easy loading of long/heavy structures.
2. Pit Type Stress Relief Furnace
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Description: A vertical furnace where components are lowered from the top. Ideal for cylindrical components.
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Applications: Headers, nozzles, large-diameter pipes.
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Benefits: Saves floor space, ideal for tall parts, better vertical temperature flow.
3. Box / Chamber Furnace
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Description: A horizontally loaded, front-access stress relief furnace.
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Applications: Tube sheets, small drums, flanges, brackets.
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Benefits: Fast cycle changes, compact design, suitable for shop floor use.
4. Continuous Conveyor Furnace (for small batch boiler accessories)
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Description: Belt or roller conveyor for continuous stress relief of fasteners, clips, or boiler brackets.
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Benefits: High throughput, minimized handling.
Technical Table – Typical Stress Relief Parameters for Boilers
Parameter | Typical Range | Notes |
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Material Grades | SA 516 Gr 60/70, SA 387, SA 192 | Carbon steel, Cr-Mo steel common in boiler fabrication |
Stress Relief Temperature | 580°C to 700°C | Depends on alloy content and code compliance |
Heating Rate | 30–100°C/hour | Per ASME guidelines, slower for thicker parts |
Soak Time | 1 hour per 25 mm wall thickness | Minimum 30 min; adjusted for total thickness |
Cooling Rate | Max 100°C/hr down to 300°C, then air | Controlled to avoid thermal shock/distortion |
Atmosphere | Air (optional: nitrogen) | Inert used for sensitive alloy steel parts |
Control System | PID / PLC + SCADA | Multi-zone control, data logging, remote monitoring |
Compliance | ASME Section I, IBR, ISO 9001 | Thermocouple placement, calibration, and data archiving required |
Industrial Applications – Boiler Parts Requiring Stress Relief
Component | Description | Recommended Furnace Type |
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Boiler Shells | Large longitudinally welded pressure shells | Bogie hearth gas fired furnace |
Steam Drums | Horizontal high-pressure drums | Bogie hearth or pit type |
Headers & Manifolds | Multi-nozzle thick-wall welded parts | Pit type furnace |
Tube Sheets | Forged plates with drilled holes | Box furnace |
Superheater Coils | Heat transfer coils with welds | Electric or gas batch furnace |
Water Walls | Panel assemblies with welding across tubes | Continuous or large chamber type |
Nozzles & Flanges | Weld-on pipe fittings | Electric batch furnace |
Standards and Quality Compliance for Boilers
Our stress relief furnaces for boiler manufacturers comply with:
Standard | Description |
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ASME Section I PWHT | Post-weld heat treatment required above threshold thickness and alloys |
IBR – India | Mandatory thermal cycle records, calibration reports, and approval testing |
ISO 9001:2015 | Process control, traceability, and quality assurance |
DIN / EN 12952 | European boiler design standards for power plants |
We provide complete documentation packages including thermal cycle charts, uniformity surveys, and SOPs for inspection authorities and customer audits.
System Design and Furnace Features
Maan Global furnaces are engineered with the following features:
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Chamber Sizes: From 1500 mm x 1500 mm to 8000 mm x 8000 mm
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Loading Mechanism: Bogie trolley, crane-guided platform, or forklift compatible
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Insulation: Ceramic fiber lining or refractory brick depending on operating cycles
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Burner System: Fully modulating with O₂ sensor and flame failure safety (gas fired units)
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Electrical System: PLC + HMI with thermocouple feedback loop and ramp-hold programming
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Energy Efficiency: Optional regenerative burners or waste heat recovery available
Optional Add-Ons for Boiler Clients
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SCADA / cloud monitoring integration
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Pressure port compatibility for vessel-mounted sensors
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Backup generator support for uninterrupted thermal cycles
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Temperature uniformity certification kit
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AMCs, calibration, and operator training
Global Installations – Maan Global Reach
As a trusted name in stress relief furnace manufacturing, we’ve supplied systems to:
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India: Hyderabad, Chennai, Pune, Ahmedabad, Howrah
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Saudi Arabia: Jubail, Dammam, Riyadh
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UAE: Sharjah, Dubai, Abu Dhabi
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Africa: Kenya, Tanzania, Nigeria, Ghana
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Bangladesh & Nepal: IBR-certified furnace setups
Contact the Trusted Supplier of Stress Relief Furnaces for Boiler Manufacturers
Whether you’re fabricating IBR-approved high-pressure steam boilers, waste heat recovery units, or utility boilers, Maan Global Industries is your ideal partner for stress relief furnaces for boiler manufacturers.
We deliver precision-controlled, ASME/IBR-compliant furnace systems tailored to your plant layout, material specs, and process load.
Email: mail@maanglobalindustries.com
Call/WhatsApp: +91-8882490101