Rebar Cold Forging Machine
IS 16172:2023 asks for one result from the cold forging step: after threading, the bar end must have at least the cross-section area of the parent bar. A rebar cold forging machine is how a coupler maker gets there. Listings also call it a TMT bar cold forging machine, and the job is the same. It grips a sawn bar end, presses it into a closed die, and leaves it larger, round and uniform. A thread then goes onto that enlarged end, so the rebar coupler joint can carry the full load of the bar.
Hydraulic rebar cold forging machine technology
The standard has hydraulic drive in mind. Its description of the upset system says the bar ends are hydraulically enlarged by cold forging. Inside a hydraulic rebar cold forging machine, two cylinders do the work. A clamping cylinder holds the bar, and a forging cylinder pushes the end into a die cavity sized for the enlargement the thread needs.
A US patent on a closed-die design describes the logic well: one force secures the bar against the axial push, and the other keeps the dies shut against the sideways swelling of the steel. Listings usually include a forging block, a few die sets with punches, and a power pack with separate high and low pressure circuits.
Working principle of a rebar upsetting machine
The work starts before the machine. A saw cuts the bar end square. IS 16172 does not allow disc cutting or gas cutting for this, because both risk overheating the bar and leaving an end out of square. It gives about 3 degrees either way as the usual perpendicularity tolerance.
Upsetting is cold forging under another name. In a rebar upsetting machine the clamped end is pushed into the die until it grows by a few millimetres. One manufacturer puts the increase at roughly 3 to 5 mm in diameter. The same patent notes that upsetting also evens out the ribs and small deviations along the end, so the thread starts from one standard diameter and a round section.
The reason for enlarging is simple. Every thread removes metal. Cut or rolled, the patent explains, a thread leaves the threaded section with less effective area than the bar, and the joint ends up weaker than the bar itself. Enlarging first gives the thread extra steel to work with.
Forging is the second step of four: saw, forge, thread, then check. After that the threaded length gets a plastic cap, which comes off only when the next bar goes in. Cutting and forging eat length, and Unbrako's bar-end guide tells users to allow extra length on each bar to cover it.
What IS 16172 expects around the forging step
IS 16172:2023 is the first revision of the Indian standard for reinforcement couplers. Annex A describes the upset parallel threaded system: bar ends sawn square, hydraulically enlarged by cold forging to a set core diameter, then threaded. Annex G, which the standard offers as guidance for site quality checks, is where the rules for whoever runs the machine sit.
The forged length has to suit the thread length in the coupler maker's design. Oversized ribs can be smoothed before forging. Double cold forging is not permitted, and a bad forging means cutting the end off square and starting again on fresh bar.
After forging, someone looks over the end for cracks, and GO and NO GO gauges check the thread major diameter. Every threaded end then takes a proof load of 80 percent of the bar's minimum yield strength on a machine that shows the load on a digital display and punches the bar itself, with no manual marking.
That ban on double forging puts weight on the die and the stroke. The machine has to finish a 32 mm end in one go, and the cavity has to match the bar. A machine that regularly needs a second hit costs you a saw cut and a length of bar each time.
The standard also ties approvals to machines. Type tests have to be repeated when the forging or threading machine changes. The slip test approval normally lasts one year, and the cyclic and fatigue approvals five. For a coupler manufacturer, swapping machines is a retesting event.
Surya hydraulic TMT bar upsetting machine specifications
Surya Engineering builds this hydraulic TMT bar upsetting machine in Mumbai in two sizes. The SE-32 takes 16 to 32 mm bars with a 5 HP motor and 2036 kN of forging force at a rated working pressure of 80 MPa. It measures 1030 by 500 by 956 mm and weighs 900 kg.
The SE-40 takes 16 to 40 mm bars with a 7.5 HP motor and 3000 kN at 31.5 MPa. It measures 1300 by 830 by 1350 mm and weighs 1250 kg.
Force is pressure times piston area, so those two figures only mean something as a pair. A listing that quotes tonnage alone says little about what the cylinder is doing.
Pick the size from your largest bar. A machine bought for 32 mm becomes a problem the week a job specification arrives with 36 mm bars. Ask how many die sets come with the machine and how long a changeover takes.
Rebar end forging machine applications
A rebar end forging machine earns its keep where bars are spliced in volume. The foreword of the standard gives the reason people go to this trouble: splicing large bars mechanically means less congestion when the concrete goes in, and faster construction. Surya's product listing names metro rail, tunnel, flyover, dam, industrial and precast work as typical uses.
Rebar coupler applications also decide how demanding the coupler has to be. Couplers pass as Class L with the low cycle fatigue test and as Class H with the high cycle test as well. The standard recommends Class H for road and rail bridges, machine foundations and tall slender structures such as stacks, so a yard that supplies bridge work should ask about the class early.
Whatever the class, the finished splice must reach 130 percent of the bar's specified yield strength, or the bar must fail outside the splice.
Rebar cold forging machine price in India
Prices are scattered. IndiaMART and Aajjo listings for machines that handle bars up to 32 or 40 mm mostly fall between about ₹2.3 lakh and ₹3.5 lakh, with outliers from ₹2.15 lakh to ₹7 lakh, and the spec rows are loose. One listing gives the power of a 16 to 32 mm machine as 240 hp, probably a voltage figure in the wrong column. Any rebar cold forging machine price you see online is an asking price, and many listings give 415 V, three phase.
Owning a machine does not always pay. Unbrako calls its upset parallel threaded coupler a fit for large scale projects, and a US patent for a competing splice describes upsetting equipment as heavy and expensive and builds its method around avoiding it. A site with a small number of splices may spend less buying bars prepared elsewhere, or choosing a splice type that skips the forging step. Past a certain volume the sums flip, so work out your own number from what you pay per prepared bar end today.
When you send an enquiry, give the largest bar diameter, the bar grade and the thread length your coupler design needs. Ask for forged samples of your own bar. Check them against the standard's own list: a square sawn end, no visible cracking, and a thread that passes GO and NO GO gauges after rolling. Get the working pressure and forging force in writing, and do all of this before you pay an advance.
Installation and Commissioning
Installation of Hydraulic Rebar Cold Forging Machine
The Hydraulic Rebar Cold Forging Machine should be installed on a stable, level and suitable industrial floor to ensure proper machine alignment and reliable operation. Correct installation helps maintain hydraulic system performance, clamping accuracy and consistent rebar end upsetting.
Installation Requirements
Foundation: Place the machine on a stable and level industrial floor capable of supporting its operating weight.
Electrical Connection: Arrange the electrical supply according to the machine's rated voltage, phase and frequency specified on its nameplate.
Machine Positioning: Maintain sufficient space around the machine for bar feeding, operation, inspection and maintenance.
Hydraulic System: Check hydraulic oil level, hoses, fittings and connections before starting the machine.
Die Installation: Select and fit the appropriate forging die according to the TMT bar diameter.
Safety Inspection: Check the clamping arrangement, emergency controls and electrical connections before operation.
Installation and Trial Operation Procedure
Position the machine on the prepared installation area.
Check the machine alignment and electrical connections.
Inspect the hydraulic system and install the required forging dies.
Perform an initial operational check according to the operating instructions.
Conduct a trial forging operation using the specified TMT bar.
Inspect the forged bar end for dimensional accuracy and visible defects before proceeding with threading.
Note: Final installation requirements, electrical ratings, hydraulic oil specifications and commissioning procedures should be followed according to the machine manual and Surya Engineering's technical instructions.
Warranty and After-Sales Service
Warranty and After-Sales Service
Surya Engineering focuses on providing reliable rebar processing machinery for construction, reinforcement fabrication and mechanical coupler manufacturing applications.
The Hydraulic Rebar Cold Forging Machine is offered with a 1-year warranty on mechanical parts, as stated on Surya Engineering's related TMT Bar Cold Forging Machine listing. Confirm that the same coverage applies to the specific hydraulic model and obtain the warranty terms in writing before publishing this claim.
After-Sales Service and Technical Support
Installation Guidance: Technical guidance regarding machine positioning, connections and initial setup.
Operating Assistance: Guidance on machine operation and the rebar cold forging process.
Maintenance Support: Assistance with routine machine inspection and hydraulic system maintenance.
Spare Parts Assistance: Support regarding replacement parts, forging dies and punches.
Technical Troubleshooting: Assistance in identifying operating issues and recommending appropriate corrective actions.
For technical support or service enquiries, customers can contact Surya Engineering with their machine model, serial number and details of the issue.
Contact Surya Engineering
Email: surya.engineers2000@gmail.com
Location: Mumbai, Maharashtra, India
Service availability, on-site visits, spare-part coverage and warranty exclusions should be confirmed in the purchase quotation.
Questions buyers ask
1. What does a rebar cold forging machine do?
It enlarges the end of a sawn TMT bar under hydraulic force. The enlarged end is then threaded for a rebar coupler.
2. Why enlarge the bar end before threading?
Threading removes metal. Forging first means the threaded section keeps at least the cross-section of the parent bar, so the joint is not weaker than the bar.
3. What bar sizes can it handle?
The SE-32 takes 16 to 32 mm bars. The SE-40 takes 16 to 40 mm bars.
4. Which model should I buy?
Choose by your largest bar, not your usual one. If you may ever process bars above 32 mm, take the SE-40.
5. What is rebar end upsetting?
It is the same operation as cold forging. Force squeezes the bar end shorter and fatter, so the diameter grows.
6. Is a TMT bar forging machine different?
Usually not. It is the same equipment under another name. Compare bar range and forging force instead of the name.
7. Does the machine cut the thread?
No. It only forges the end. Threading is the next step on a threading machine.
8. Can I forge a bar a second time if the first attempt fails?
No. IS 16172 does not permit double cold forging. Cut the end off square and forge again from fresh bar.
9. What checks follow forging?
Look for cracks, then check the thread with GO and NO GO gauges. Proof load every threaded end to 80 percent of the bar’s minimum yield strength.
10. How do I get a price?
Send your largest bar diameter, bar grade and quantity. Surya will quote the right model.
