1. Relationship LHA, LHT and LHC H-beam Welding Machine:
1) LHT Versus LHA H-beam Submerged Arc Welding Machine:
a) At first glance, LHT model T frame machine looks very similar to LHA series gantry type machine, especially center control LHAZ models:
i. Wuxi JACK LHT model machine: (Fig.1)
ii. Wuxi JACK LHAZ model center operating type machine: (Fig.2)
b) Shown in the above photos, the LHT model has its two pieces of workpiece laid on support in open structure, so LHT can be used for welding larger size of H Beam, and it has extensive accommodation on varied H Beam size. In theory, there is no confinement on dimension of H Beam to be available being welded;
c) While the LHA model machine has its workpieces supporting rack surrounded in an enclosed frame. So, there is series of concrete models for corresponding fitting size range of H Beams;
2) Connection between LHC and LHT H-beam Welding Machine:
a) H Beam Size: Same as LHC, in LHT model, because H Beam are put on the supporting tacks outside of machine frame column, there is no limit to the extension of H Beam. In this sense, for the same size of machine frame, H Beam welded with LHT model can be larger (web height) than that of LHA series;
b) Machine Model: Also same as LHC, such structure can accommodate on H Beam of various web heights, so for LHT H-beam Gantry Welding Machine, there is no variation in machine model to differentiate, just like one model of LHT applicable for all size of H Beam;
2. Drive Mode on H-beam Submerged Arc Welding Machine:
a) Unlike heavy power involved during H Beam assembling step of H Beam Assembly Machine, and during straightening step in H Beam Straightening Machine, which need hydraulic system to provide power momentum,
b) In LHT, LHC and LHA models H-beam Welding Machine,
Driving power on main units is with:
1) Motor reducer for driving on mechanical system, body (T frame, gantry, column trolley) movement along rails;
2) Electric power for powering on SAW welding power source;
3) Pneumatic gas cylinder system for driving welding arc tracing unit;
3. Three Types of SAW Welding Modes in H-beam Welding Machine:
1) Single Arc of SAW Technology in H-beam Submerged Arc Welding Machine:
a) This refers to “single piece of welding wire generates single welding arc”: (Fig.3)
b) Welding seam size: With this type of SAW technology, welding height of each pass of welding seam is around 10mm;
c) Characteristic: In such case, one set of welding power source is used for welding one piece of workpiece;
d) Quantity of Welding System: So, one set of LHA and LHT model machine should be equipped with two sets of welding power source, and one set of LHC with one set of welding power supply;
e) Working site of Wuxi JACK LHA model single arc SAW H-beam Gantry Welding Machine: (Fig.4)
2) Tandem Arc of SAW Technology in H-beam Welding Machine:
a) This refers to “Two pieces of welding wire generate double welding arc”: (Fig.5)
b) Welding seam size: It is the “The heaviest welding mode”. With tandem arc SAW, welding height of each pass welding seam can be up to 20mm;
c) For this reason, for H Beam with web thickness above 20mm (usually we call such H Beams as “thick ones”), customers have two options on configuration of corresponding machines:
i. Either adopts with Single Arc discussed in the previous segment. The gantry frame moves back and forth along rails two times, and at the same time performing SAW welding on H Beam two times;
ii. Or, adopts with Tandem Arc SAW technology. Under such condition, the machine can finish SAW welding on H Beam with single pass welding. So, it doubles productivity on H-beam welding for customers;
d) Quantity and Specifications of SAW Welding Power Supply in H-beam Submerged Arc Welding Machine:
i. To implement on Tandem Arc SAW, two sets of welding power source should be used for welding on one piece of H Beam, which is one set of A.C. and one set of D.C. power supply respectively;
ii. So, in one set of LHA or LHT model machine, there should be totally 4 sets of SAW power supplies, 2 sets of D.C. type and 2 sets of A.C. type respectively; For one set of LHC model machine, the quantity is half that of LHA and LHT model:
Tandem arc SAW in Wuxi JACK LHC model H-beam Welding Machine: (Fig.6)
iii. The welding current specification of D.C. and A.C. SAW power supplies depends on the max. thickness of H Beam flange for welding, usually in the range of 1000A to 1600A;
3) Twin Arc of SAW Technology in H-beam Gantry Welding Machine:
a) This refers to “Two pieces of welding wire generate single welding arc”: (Fig.7)
b) Application: Twin arc SAW is usually applied in 0° flat fillet welding position on H Beam. 0° flat fillet welding means H Beam is put flat at horizontal position, while welding torch is at 45°; The PHJ and ZHJ series 3 in 1 H-beam Welding Machine developed by our company is adopted with 0° flat fillet welding:
0° flat fillet welding in Wuxi JACK 3 in 1 machine on H Beam welding: (Fig.8)
c) As comparison, the 45° fillet welding used in LHT/ LHC/ LHA sole purpose H-beam Submerged Arc Welding Machine is, H Beam is put at 45° position, while welding torch is at straight vertical downward position:
45° fillet welding in Wuxi JACK H-beam Gantry Welding Machine: (Fig.9)
d) Advantage of Twin Arc SAW for H-beam Submerged Arc Welding Machine:
i. 0° flat fillet welding is not as easy as 45° fillet welding in terms of producing welding seam of good appearance. However, with adoption of Twin Arc SAW welding, this target can be met;
ii. Also, Twin Arc SAW welding can raise welding speed around 5%, making contribution to high efficiency of production;
4. Operation on H-beam Welding Machine:
1) For Operators of H-beam Gantry Welding Machine:
a) Before official taking charge on the position, operator should read and understand machine manual book, being familiar with structure/ operation and adjustment, has capability of operating all function units, especially SAW welding power supply, and the machine itself;
b) Operator should have trial run on the machine first;
c) Being familiar with all the pushbuttons and switches of machine operating panel;
d) Confirm on all units of the H-beam Submerged Arc Welding Machine are in normal state;
e) Make adjustment on welding parameters of SAW power supply;
In all, make fully preparation on SAW welding operation ahead of time;
2) Service on H-beam Submerged Arc Welding Machine:
As machine with frequent to-and-fro mechanical frame movement during work, arrangement of electric cables is very important:
a) For those involved along with movement of mechanical frame, cables are deployed with overhead hanging rack alongside the rails;
b) For those involved with movement along horizontal beam of mechanical frame, cables are deployed with drag chain;
c) Working site of Wuxi JACK LHT model H-beam Gantry Welding Machine, with cables arrangement: (Fig.10)
3) To have easy maintenance on the machine, there is overhead platform on top of mechanical frame, surrounded with guard rail, and accessed with ladder: (Fig.11)
4) Safety Alarm: For purpose of being informed immediately when contingency happens, there is alarm light being fit at top of machine main frame, very eye catching.
5. SAW Welding Power Supply Choice and Work Principle for H-beam Submerged Arc Welding Machine:
1) SAW Power Supply in H-beam Welding Machine:
a) Wuxi JACK Choice: Submerged arc welding is the core step in manufacturing process of welding H Beam, which directly affects on quality of finished H Beam. For this reason, the SAW power source we outsource for LHA, LHC and LHT models, is of the top level in the welding equipment industry;
b) With years of test, validation and feedback from customers, in terms of the optimum quality together with reasonable price/ friendly operation and service, we recommend two options on SAW power source to be used in the machines:
i. Chinese Brand HUAYUAN SAW welding machine: (Fig.12)
ii. U.S. Brand Lincoln SAW welding machine: (Fig.13)
Both models are capable of providing single arc/ twin arc/ tandem arc SAW welding;
c) Of which the Chinese HUAYUAN has very good cost performance. It is stable and consistent in delivering high standard of SAW welding quality, with reasonable equipment price. Nowadays, HUAYUAN is one of the main brand SAW power supplies, in the field of steel structure BOX I H Beam welding;
2) Technical View on SAW Power Supply in H-beam Gantry Welding Machine:
a) Function of SAW Power Supply in H-beam Welding Machine:
i. ZD7 series inverter control integrated function power source can be used in diversified welding mode, including automatic submerged arc welding, electroslag welding, sticking welding and arc air gouging;
ii. Besides, this power supply also has very satisfactory delivery on DC single wire welding and strip surfacing;
b) Characteristic of SAW Power Supply in H-beam Submerged Arc Welding Machine:
i. The main control circuit of this ZD7 SAW power source is of IGBT inverter circuit. It has strong points of superior dependability, quick reaction time, and consummate dynamic characteristic;
ii. The ZD7 SAW power source has capability of compensating automatically against potential risk of grid voltage fluctuation, making sure stable and consistent arc burning during SAW welding period, as well as guaranteeing good appearance and high intensity welding seam generated;
3) Work Principle of SAW Power Supply in H-beam Welding Machine:
ZD7 series inverter control integrated capability welding power supply utilizes inverter main circuit as its control loop, as shown below:
a) During SAW welding operation, the three phase A.C. power from workshop utility is converted to 20KHz high frequency D.C. current, after being rectified through three phase rectifiers;
b) By means of the IGBT inverter, this high frequency D.C. current will be inverted to A.C. high frequency current as transition;
c) Following that, this inverted A.C. high frequency current will be rectified back to D.C. current again: With the continuous going through voltage diminishment in the high frequency transformer, the A.C. current is rectified to D.C. type back again;
d) This D.C. current is then filtered through reaction loop, and controlled by the signal from the current negative feedback;
e) After being amplified, this negative feedback signal is fed into the inverting interface of the error amplifier, and running through the pulse width adjusting integrated circuit;
f) By this time, this amplified signal can control the working time of IGBT, and hence inverter rectifier can get the required external characteristic, for getting the expected performance of the H-beam Submerged Arc Welding Machine;
4) Control console of tandem arc SAW power source equipped with Wuxi JACK H-beam Gantry Welding Machine: (Fig.14)
![Fig14 H-beam Welding Machine 53]( "Fig14 H-beam Welding Machine 53")
6. SAW Welding Flux Sending and Recycling Unit of H-beam Gantry Welding Machine:
1) Working Complex in H-beam Welding Machine:
a) Outline: The automatic H-beam Submerged Arc Welding Machine is comprehensive group integrating management of outsourced components into one machine control;
b) Importance: Conceivably, quality of these purchased units plays important role in quality assurance of machine performance on H Beam welding;
c) Besides SAW welding power supply, another important outsourced component is used is SAW welding flux conveying and recycling unit, which affect on SAW welding quality and running cost in large degree. For this unit we choose Chinese brand, to be specifically, Wuxi local supplier of LIANTONG brand:
2) Flux Convey and Recycling Unit in H-beam Submerged Arc Welding Machine:
a) SAW welding flux yellow color hopper and grey color reuse machine: (Fig.15)
b) Brief: LTHS-E-type flux recovery and recycling unit can be used as assisting mechanisms for all kinds of welding process, which involve recycling flux for use, such as submerged arc welding;
c) Formation of Flux Recovery and Recycling Unit in H-beam Welding Machine:
i. This unit is composed of main body of the recovery unit, flux hopper, stainless steel pipe, connection hose and suction tip;
ii. Its flux hopper is installed on the front side horizontal beam of H-beam Welding Machine, with its main body on the top of mechanical frame;
iii. Flux suction tip is installed on the front end of welding torch;
iv. Connection among main body, flux hopper and suction tip in this unit is by way of stainless steel tubes and hoses;
v. In this way, it forms a complete set of automatic flux circulating, transmission and recovery system;
3) Working Principle of Flux Recovery and Recycling Unit in H-beam Welding Machine:
a) Operation of the flux recovery and recycling unit is integrated with electric control system of H-beam Welding Machine itself;
b) By means of two pneumatic valves, the storage bucket is divided into three sections of recovery bucket, transition bucket and feeding bucket;
c) During welding operation, fluxes are sent from recovery bucket into feeding bucket by way of transition bucket, without necessity of shutting off the entire unit;
d) When flux volume inside the feeding bucket becomes less than 15kg, the recovery unit will give alarm, so that the entire system will always work normally during SAW operation of H-beam Gantry Welding Machine;
4) For more details on installation, operation and maintenance of the SAW welding flux recovery and recycling unit, customer can check manual book and diagram of the unit, together with other technical documents, submitted to customers of H-beam Welding Machine.
