Lincoln Electric IM790 manual Changing Machine Over to Feed Other Wire Sizes, Process Guidelines

B-6	OPERATION
		B-6

9.To stop welding, release the gun trigger and then pull the gun away from the work after the arc goes out.

10.When no more welding is to be done, close valve on gas cylinder (if used), momentarily operate gun trigger to release gas pressure, and turn off the SP-175 Plus.

Cleaning Tip And Nozzle

Clean the contact tip and nozzle to avoid arc bridging between the nozzle and contact tip which can result in a shorted nozzle, poor welds and an overheated gun. Hint: Anti-stick spray or gel, available from a welding supply distributor, may reduce buildup and aid in spat- ter removal.

CAUTION

It is important when changing between welding with steel wire and aluminum to exchange feeding components due to the lubricant applied to steel wire. Failure to do so may result in contaminated welds when welding aluminum.

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TABLE B.1 — SP-175 Plus Welding Procedures

		Shielding		Voltage/Wire Speed
Process	Welding Wire	Gas	22 ga	16 ga	12 ga	1/8”	3/16”	1/4”
	.035 Dia(0.9mm	100% Argon	B-5	B-7	E-9	G-9	I-9	J-10*
	4043 Aluminum
	Wire
MIG DC+			16 ga	14 ga	12 ga	10 ga
	.030 Dia	98% Argon/	A-3	C-6	D-7.5	D-7.5
	308L Stainless	2% Oxygen
	Steel Wire

PROCESS GUIDELINES

The SP-175 Plus can be used for welding mild steel using the GMAW, single pass, process which requires a supply of shielding gas or it can be used for the self shielded, Innershield electrode process.

The recommended gas and electrode for GMAW is welding grade mixed CO2 and Argon (75-80%) gas and 0.025” (0 6 mm) diameter Lincoln Super Arc L-56 mild-steel welding wire. For 14 gauge (2,0 mm) and thinner CO2, or blended gas is acceptable. A mixed gas consisting of 75 to 80% Argon and 20 to 25% CO2 is recommended for welding on heavier gauge [12 gauge (2,5 mm) for example] steel.

The recommended electrode for the self-shielded process is 0.035” (0,9 mm) diameter Lincoln Innershield NR-211-MP. This electrode can be used for all position welding of 20 gauge through 5/16” (1,0

–8,0 mm) thick steel [multiple passes are required for 1/4” and 5/16” (6,0 and 8,0 mm)].

WARNING

Use of the GMAW process with the SP-175 Plus on thicker materials than 5/16” (8.0 mm) may result in poor welds. The welds may “look” good, but may just be “sitting” on top of the plate. This is called “cold casting” and will result in weld failure.

The SP-175 Plus is suitable for .035" Aluminum wire and .030"-.035” stainless wire. Refer to Table B.1 for Recommended Procedure Settings. Aluminum wire requires an Aluminum Welding kit. See ACCES- SORIES section.

*Test assembly preheated to 250° F.

CHANGING MACHINE OVER TO FEED OTHER WIRE SIZES

The SP-175 Plus is shipped from the factory with a gun liner ready to feed 0.023-0.035” (0.6-0.9 mm) diameter wire. The contact tip is 0.025” (0.6 mm) and the drive roll is set for 0.023”-0.025” (0.6 mm). To operate the SP-175 Plus with other sizes of wire, it maybe necessary to change the contact tip, and Gun Liner Configuration. Refer to the maintenance section for component configuration and replacement proce- dures

WELDING WITH FCAW (Innershield)

Welding with Innershield requires an Innershield Welding Kit. A gasless nozzle is provided in the Innershield Welding Kit. When using Innershield elec- trode, installing the gasless nozzle will improve visibili- ty of the arc and protect the gas diffuser from weld spatter. Additionally included is a gun cable liner to permit proper feeding of .035” (0,9 mm) Innershield wire. Refer to the ACCESSORIES section for details on obtaining this kit.

SP-175 PLUS