KÖCO 1602 E-, used stud welder

KÖCO 1602 E- is a thyristor direct current power source for stud welding with a drawn arc, sold together with a K 24 gun. You adjust the current steplessly from 200 A to 1600 A, at a 100% duty cycle the machine gives 500 A, and the open circuit voltage is 95 V. The K 24 torch handles studs of diameters from 13 mm to 22 mm.

What this machine is for

This is equipment for stud welding, that is an arc and pressure process. The current melts the face of the stud and the surface of the base material, and then the part is pressed mechanically into the liquid bath, where it sets together with the base. A reserve of 1600 A at a 10% duty cycle lets you make a large volume of liquid metal in a short time, so that the face of a stud of 22 mm diameter melts across the whole section. At smaller diameters the machine runs continuously at 500 A, so it suits a line where studs go one after another without breaks to cool the power source.

The documentation directs this set to engineering and bridge structures, where SD type shear connectors of Ø 16, Ø 19 and Ø 22 mm diameter are welded and the joints have to meet the demands of the ISO 14555 standard. The second group of uses is prefabrication of tanks and welding of insulation pins in continuous mode, shipbuilding when fixing pipelines and insulation on bulkheads, power generation when fitting anchors in steam boilers, and robot cells that make use of the high duty cycle.

Thyristor control gives stepless current adjustment and a weld time set up to 1500 ms, with a lower limit of 20 ms. Thanks to that you handle three variants of the process: with a ceramic ferrule (CF), under gas shielding (SG) and the short cycle Short-Cycle for small studs on thin sheet, where low thermal distortion counts.

Features and equipment

• Open circuit voltage 95 V: the high potential strikes the pilot arc also on a surface with traces of zinc, scale or light corrosion, and the arc column is stiff, so the process does not go out before the stud is set. That limits mechanical cleaning of parts before welding.
• Stepless current adjustment from 200 A to 1600 A: with one power source you handle small studs and heavy shear connectors, and you also match the energy to aluminium and stainless studs with the right shielding gas. The lower limit of 200 A gives a reserve of sensitivity where too large a portion of energy would burn through thin sheet under the stud.
• Weld time control up to 1500 ms with a lower limit of 20 ms: the same equipment runs a long cycle for thick diameters and a short Short-Cycle on thin sheet.
• Thyristor bridge: the system corrects the output parameters in real time when the mains voltage drops, it has a high thermal inertia and takes surges better than inverter electronics on a building site. With a supply from a temporary distribution board that is often the difference between working and a station standing still.
• Continuous work at 500 A with a 100% duty cycle: the machine can stand in an automated line and work in a robot cell without breaks to cool the transformer, which in prefabrication of tanks and insulation pins translates straight into the number of studs set per shift.
• Class F insulation and forced ventilation: the windings take a higher working temperature, and the forced air flow takes the heat away, so the periods between services are longer in multi shift work.
• KÖCO Classic K 24 gun: a torch in a reinforced build for studs of diameters from 13 mm to 22 mm in a ceramic ferrule, with current cables that take currents of the order of 2000 A without overheating. The ceramic ferrule supports the weld pool and centres the stud, which on shear connectors on bridges decides the shape of the joint.
• Automatic length compensation in the K 24 torch: the lift height of the stud stays the same despite differences in stud length and unevenness of the sheet, so every joint gets the same portion of energy, and the fillet has a repeatable geometry, which technical supervision judges by eye. The mechanism takes part of the responsibility for repeatability off the operator, but it needs to be kept clear and checked regularly.
• Three variants of the process: with a ceramic ferrule (CF), under gas shielding (SG) and short cycle (Short-Cycle), that is one power source for heavy connectors and for small studs on thin sheet.

Technical data

What you get

• KÖCO 1602 E- thyristor power source
• KÖCO Classic K 24 gun with automatic length compensation

What to watch out for

The product record gives a welding current up to 200 A, and the source description a range from 200 A to 1600 A, so confirm the value on the rating plate before you buy. The peak draw is 190 A at 380 V, so with studs of Ø 19 and Ø 22 mm diameter the documentation recommends a slow blow class D fuse, 63 A or 80 A. Without such a circuit the machine will trip the fuse in the middle of a cycle, and there is no way around it with settings.

The K 24 torch is matched to large diameters from 13 mm to 22 mm, for smaller studs the maker provides K 22 series guns with a different spring and lift mechanism characteristic, so count that cost if you plan small studs. Welding under gas shielding and in the Short-Cycle variant also needs gas equipment and the right studs, the power source alone will not replace that. The current contacts in the torch and the clear working of the length compensation mechanism need regular checks, because the repeatability of the joint depends on them. The source description does not list earth cables, a stand or a stock of ceramic ferrules, so confirm what the set holds before you buy.

This unit is sold

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