Made in Japan

More Economic and More Safe with Gas Pressure Welding

Japanese Industrial Standards Japan Reinforcing Bar Joints Institute Concrete Steel Reinforcing InstituteJapan Society of Civil Engineers

Gas Pressure Welding Equipment

The gas pressure welding method was similarly developed in the United States and Japan in the 1930s. Since then, it has found wide appli-

cation in construction and is commonly used to weld steel reinforcing bars. Among all types of joints in Japan, currently, the welded joints

accounts for approximately 90%, and the majority is excuted by gas pressure welding. The reason is that gas pressure welding is superior

in workability to other joining methods for this application. By exploiting this method, the mechanical properties of rebars joints will be

highly improved. This method has higher mechanical properties and much more cost saving compare with other rebar joining methods like

conventional overlap method or coupling method.

Gas pressure welding process

This method is not classified as a fusion welding but a solid state welding one, in which the joining process can be performed without melting

the base metal. Atomic diffiusion and reconfiguration along with the bars’ interface occur by simultaneous processes of heating higher than

recrystallization temperature (at about 1200-1300 degrees centigrade) and exerting external pressure. This method is executed as follows: 1)

butting the end surface of materials against each other, 2) heating the interface by oxyacetylene flame with pressure applied and 3) stopping

the heating and pressure when upsetting length reaches the predetermined value.

. . . Features and fundamental . . .

The gas pressure welding method was similarly developed in the United States and Japan in the 1930s. Since then, it has found wide appli-

cation in construction and is commonly used to weld steel reinforcing bars. Among all types of joints in Japan, currently, the welded joints

accounts for approximately 90%, and the majority is excuted by gas pressure welding. The reason is that gas pressure welding is superior

in workability to other joining methods for this application. By exploiting this method, the mechanical properties of rebars joints will be

highly improved. This method has higher mechanical properties and much more cost saving compare with other rebar joining methods like

conventional overlap method or coupling method.

Gas pressure welding process

This method is not classified as a fusion welding but a solid state welding one, in which the joining process can be performed without melting

the base metal. Atomic diffiusion and reconfiguration along with the bars’ interface occur by simultaneous processes of heating higher than

recrystallization temperature (at about 1200-1300 degrees centigrade) and exerting external pressure. This method is executed as follows: 1)

butting the end surface of materials against each other, 2) heating the interface by oxyacetylene flame with pressure applied and 3) stopping

the heating and pressure when upsetting length reaches the predetermined value.

. . . Features and fundamental . . . . . . Merits . . .

Whole time of operation: 5 minJoining time for rebar size 25mm: 90 secs

• Reaction of steel bar under bending test • Reaction of steel rebar under excessive stress

• Eliminating of overlap cause significant savings

Merits of gas pressure weldingReinforcement of concrete structures due to the higher mechanical properties of joining zone higher than the rebar itself.

Reduction of rebar consumption due to elimination of the overlap and also scraps.

Saving time and cost in compare to other mechanical joining mehods such as coupling.

Saving cost due to elimination of human error and unpredictable working situations.

Savings1- 30% saving in consumption of rebars by eliminating the overlap zone and wastes.

2- Saving the time of execution.

3- Less work force is required

4- Reduction of transportation on account of reducing material consumption.

5- Joining the wasted rebars and reusing

Retrofitting and better implementation1- By removing overlaps, structural weight is descended; thereby, the lateral forces of gravity is decreased and the strength of the structure

towards earth quakes will be boosted.

2- Appropriate concreteing up and better vibration of concrete will be provided due to reduction of unnecessary volume of rebars in joining

areas.

3- Better involvement between concrete and rebars because of eliminationg extra rebars.

4- Boosting the mechanical strength at the joining point due to increasing the surface area.

5- Maintaining the integrity of force at the junction.

6- Physical and mechanical propertise of the junction is the same as base material of the bar.

Merits of rebar gas pressure welding

Gas pressure welding qulification test

. Visual test (VT)

1- AS/NZS 1554.3:2014; Structural steel welding , part 3: welding of reinforcing steel, non-fusion welding processes-flame pressure welding2- JIS Z 3881:2009; Standard qualification procedure for gas pressure welding technique of steel bars for concrete reinforcement3- JIS B 6801:1991; manual blow pipes for oxyacetylene welding4- JIS Z 3062:2009; Method and acceptance criteria of ultrasonic examination for gas pressure welds of deformed steel bars for concrete reinforcement5- KS D 0244:2009; Method of inspection for gas pressure welded joint of steel bars for concrete reinforcement

Standards

1- USA,Concrete reinforcement steel institute2- Japan, Reinforcing bar joints institute3- Japan, Society of civil engineers4- Iran, Road,housing & urban development research center5- Iran, Construction engineering organization

Certificates

. Bending test . Ultrasonic test

. Tensile test

Qualification methods and standards

. . . Riken services . . .

Riken services - Implementation of gas pressure welding

- Easy to operate during execution- High speed- ability to work in all cases- Compatible with the environment- Portable

- Repair and maintenance- One-year warranty - Ten years after sales service

Merits

Services and support

Riken services - Gas pressure welding equipment sales

. Column rebars

. Foundation rebars

. Shear wall rebars

. Short length rebars

. Wasted rebars

OS1-PMCode

Operation switchDescription

Switch On/Off the hydraulic pump Used

1B-HCode

High pressure oil hose (700 bar)Description

2R-JCodeRAM cylinDescription

F1-PMCode

Rebar weldingDescription

35-18used for Bar diameter size (mm)

8.4 Kgbase

RW1-BCode

Ratchet wrenchDescription

HP1-RCodeHydaulic Pump (700bar) with pressure

regulatorDescription

14.8Waight(kg)

Hydraulic pump/Electric motor drive pump Required pressure on longitudinal axis of rebars for joining them during gas pressure welding process is provided by hydraulic pump.

Ratchet wrench

Rebar welding baseRebar welding base consists of both fixed and movable jaw. It is used for keeping the rebars aligned and transfering the pressure which is exerted on the movablejaw by RAM cylinder to the rebars.

High pressure oil hose

RAM cylinder for rebar welding base

Operation switch

. . . Equipment . . .

OS1-PMCode

Operation switchDescription

Switch On/Off the hydraulic pump Used

1B-HCode

High pressure oil hose (700 bar)Description

2R-JCodeRAM cylinDescription

F1-PMCode

Rebar weldingDescription

35-18used for Bar diameter size (mm)

8.4 Kgbase

RW1-BCode

Ratchet wrenchDescription

HP1-RCodeHydaulic Pump (700bar) with pressure

regulatorDescription

14.8Waight(kg)

Hydraulic pump/Electric motor drive pump Required pressure on longitudinal axis of rebars for joining them during gas pressure welding process is provided by hydraulic pump.

Ratchet wrench

Rebar welding baseRebar welding base consists of both fixed and movable jaw. It is used for keeping the rebars aligned and transfering the pressure which is exerted on the movablejaw by RAM cylinder to the rebars.

High pressure oil hose

RAM cylinder for rebar welding base

Operation switch

. . . Equipment . . .

used for bar diameter size (mm)

Code

35-18 C35-K

41-18 C41-K

used for Bar diameter size (mm)Code

35-1835M-B

41-18 41K-B

Description used for Bar diameter size (mm)Code

Gas mixture tube 32-18 MP32-S

Gas mixture tube35-18 MP35-S

Description used for Bar diameter size (mm)

Code

Ring burner35-18 25S-RB

Ring burner 32-18 32S-RB

Ring burner 25-1835S-RB

Description Code

Acetylene/Oxygen twin gas hoseOAH1-B

Description Code

Gas pressure regultor for Acetylene gas

1-OM

Description Code

Gas pressure regulator for Oxygen gas

1-AM

Description Code

Tool box1-BX

Rebar cutter equipped with diamond sawDuring the process of gas pressure welding, the ends of the rebars must be cut right-angled. Rebar cutter equipped with diamond saw can cut the rebars right-angled, cold and clean.

Diamond saw blade

Gas mixture tube & super valve

Toolbox

Gas mixure tube is used for mixing the oxygen and acetylene gases together and super valve is used for regulating the flame condition.

Ring burner

Regultor for Acetylene gas Regultor for Oxygen gas

The gas mixture of oxygen and acetylene is burned in this section. The ring burner is designed for covering all parts of the joining rebars during the heating up process.

Gas Hose

. . . Equipment . . .

How to contact Riken toolsIran Office: Second floor, No.528, West Taleghani st., Sarparast st. corner,Tehran, IranTel: +98 21 61948 - Extention: 3

Email: Info@puyagostar.comWebsite: www.puyagostar.com

Fax: +98 21 66412844

Tel: +81-22-224-1116 Fax: +81-22-224-1140 (Japanese language only)Japan Office: 1F, Sendai Hokushin building, 1-6-10, Aoba-ku, Sendai, Japan

Gas Pressure Welding Equipment