Therm process Engineering Pvt. Ltd. designs, installs and commissions roller hearth furnaces for continuous heat treatment of tubes and bars. In a roller hearth furnace, driven rollers carry long products through heating, soaking and cooling zones at a set speed. Every piece therefore gets the same thermal cycle. Therm process has supplied gas-fired roller hearth furnaces for bright annealing carbon steel tubes, and electrically heated roller hearth furnaces for tempering martensitic stainless and low alloy steel bars. Share your product size and hourly output to discuss a line.
What Is a Roller Hearth Furnace?
A roller hearth furnace is a continuous furnace whose hearth is a row of driven rollers. Tubes, bars or trays are placed on the rollers at the entry end. The rollers turn and carry the charge through the furnace, and the product exits at the far end fully treated.
The rollers set the travel speed, and the zones set the temperature profile. Together they fix the time and temperature each piece experiences. This is why roller hearth furnaces are chosen for high-volume annealing and tempering, where batch-to-batch variation would be a problem.
For bright annealing, the furnace is sealed and run under a protective atmosphere. It is followed by a cooling section, so tubes leave clean and oxide-free. For tempering, the furnace holds hardened bars at a sub-critical temperature to restore toughness.
Compared with batch furnaces, roller hearth lines give steady throughput, easy integration with upstream and downstream equipment, and less manual handling.
Therm process Roller Hearth Furnaces
Therm process has designed, installed and commissioned roller hearth furnaces for two main duties.
Roller hearth annealing furnace (bright annealing of CS tubes). This is a gas-fired furnace, on LPG or natural gas, for bright annealing of carbon steel tubes. The reference installation handles 1500 kg/hr of tubes from 25 to 100 mm OD and 3 to 8 mm wall thickness. The maximum operating temperature is 1000°C.
Roller hearth tempering furnace (bars). This is an electrically heated furnace for tempering martensitic stainless steel and low alloy steel bars. The reference installation runs at 750 kg/hr for bar diameters of about 5 to 25 mm and lengths of 4 to 5 m. It operates at 650-800°C.
Fuel-fired designs use Therm process burners, and each burner can be calibrated with Therm process limiting orifice valves. Roller speed, zone temperatures and controls are engineered around the product mix. Microprocessor-based controls hold the profile steady.
Technical Specifications
| Parameter |
Annealing Furnace (Reference) |
Tempering Furnace (Reference) |
| Furnace Type |
Continuous roller hearth |
Continuous roller hearth |
| Process |
Bright annealing |
Tempering |
| Capacity |
1500 kg/hr |
750 kg/hr |
| Charge Material |
CS tubes |
Martensitic SS, low alloy steel bars |
| Charge Size |
25-100 mm OD x 3-8 mm thk |
~5-25 mm dia x 4-5 m length |
| Heating |
Gas fired (LPG / NG) |
Electrically heated |
| Operating Temperature |
1000°C max |
650-800°C |
| Atmosphere |
Protective atmosphere (as per process) |
As per process |
| Temperature Control |
Microprocessor-based, zone-wise |
Microprocessor-based, zone-wise |
| Customization |
Capacity, size range, zones, heating and cooling as per requirement |
|
Key Features
- Continuous throughput Rollers carry product at a fixed speed for a consistent cycle.
- Proven reference designs For tube bright annealing and bar tempering.
- Gas or electric heating Chosen according to process and site energy.
- Zone-wise temperature control Separate heating and soaking zones.
- Bright annealing capability Sealed furnace with protective atmosphere and cooling section.
- Precise burner calibration Therm process limiting orifice valves set each burner's flow.
- Line integration Entry and exit tables can link to straightening, cutting or inspection.
How a Roller Hearth Furnace Works
- Loading Tubes or bars are placed on the entry roller table, individually or in rows.
- Heating Driven rollers carry the charge into the heating zone, where burners or elements raise it to process temperature.
- Soaking The product passes through soaking zones held at setpoint long enough for full-section treatment.
- Cooling For bright annealing, the charge enters a protected cooling section to avoid oxidation. For tempering, it cools as the process requires.
- Discharge Treated product exits onto the delivery table.
- VerificationHardness, surface condition or microstructure are checked against specification.
Applications of Roller Hearth Furnaces
- Bright annealing of carbon steel tubes Softening cold-drawn tubes with a clean surface for further drawing or final use.
- Tempering of bars Restoring toughness in hardened martensitic stainless and low alloy steel bars.
- Stress relieving of tubes and bars Removing drawing and straightening stresses.
- Normalizing of suitable long products, where the line is designed for it.
Industries Using Roller Hearth Furnaces
- Tube and pipe manufacturing Cold-drawn CS tubes for boiler, heat exchanger, automotive and general engineering use.
- Bright bar and bar processing Tempering of stainless and alloy steel bars.
- Automotive component supply chain Tubes and bars used in shafts, hydraulic lines and structural parts.
- Engineering steel producers requiring continuous, repeatable heat treatment.
Benefits of a Roller Hearth Furnace
- Repeatable properties Each piece gets the same time-temperature profile.
- High productivity with continuous operation and minimal manual handling.
- Clean surfaces in bright annealing mode, reducing pickling.
- Lower labour per tonne than batch loading and unloading.
- Easy line integration with upstream drawing and downstream finishing.
Custom Roller Hearth Furnace Solutions
Therm process designs roller hearth lines around:
- Material and grade
- Tube OD and wall thickness, or bar diameter and length
- Required output in kg/hr
- Process: bright annealing, tempering, stress relieving or normalizing
- Process temperature and soak time
- Atmosphere and cooling requirement
- Gas or electric heating
- Roller material and pitch
- Entry and exit handling equipment
- Automation and data recording
- Available bay length and layout
Why Choose Therm process?
- Since 1997. Mumbai-based industrial furnace and burner manufacturer.
- Designed, installed and commissioned roller hearth furnaces for tube annealing and bar tempering.
- In-house burners and flow control, including limiting orifice valves.
- Wide annealing range: bright annealing, solution annealing, strand annealers and binding wire furnaces.
- ISO 9001 & ISO 14001 certified, as stated by the company.
Related Therm process Products
- Bright Annealing Furnace
- Tempering Furnace
- Solution Annealing Furnace
- Strand Annealer
- Industrial Burners
- Limiting Orifice Valve
Frequently Asked Questions
Q1. What is a roller hearth furnace?
A roller hearth furnace is a continuous furnace in which driven rollers carry tubes, bars or trays through heating, soaking and cooling zones. It gives every piece the same heat treatment cycle.
Q2. What is a roller hearth furnace used for?
It is used for continuous bright annealing of tubes, and for tempering, stress relieving and normalizing of bars and long products. Therm process has supplied roller hearth furnaces for bright annealing CS tubes and tempering alloy and stainless bars.
Q3. What capacity roller hearth furnaces has Therm process supplied?
Reference installations include a 1500 kg/hr gas-fired bright annealing furnace for CS tubes, and a 750 kg/hr electrically heated tempering furnace for bars. Capacity is designed to suit each line.
Q4. What tube sizes can be bright annealed?
The Therm process reference furnace handles CS tubes from 25 to 100 mm OD with 3 to 8 mm wall thickness. Other size ranges can be engineered on request.
Q5. Can roller hearth furnaces be electrically heated?
Yes. Therm process's roller hearth tempering furnace is electrically heated and operates at 650-800°C. Gas firing on LPG or natural gas is used for its high-temperature annealing furnace.
Q6. When is a roller hearth furnace better than a batch furnace?
A roller hearth furnace suits high, steady volumes of uniform long products that need identical treatment. Batch furnaces suit mixed loads, coils or lower volumes.
Q7. What information is needed for a quotation?
Share the material, product dimensions, output in kg/hr, process, temperature, atmosphere, preferred heating mode and available line length.
Looking for a Roller Hearth Furnace Manufacturer in India?
Tell Therm process what you need to anneal or temper continuously. Share your material, tube or bar size, output in kg/hr, process temperature, atmosphere, heating preference and plant location. Our engineers will propose a roller hearth line to suit.
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