Q: Our shop does a lot of MIG welding. About half of it is higher-volume production work and half is one-time special orders. Are there ways that we can manage our shop's operating costs?

A: This subject is on everyone's mind now, and there are many easy things that you can do to reduce and control costs for your GMAW (MIG) shop.

Procedure. Many shops allow too much procedural freedom to individual welders in the ways they set their machines for higher-volume production welding. For example, if we know that a quality weld can be made by setting a wire feed speed for .045” ER70S-3 wire at 370”/min., but a welder sets his machine to 335”/min. because he/she likes the way it runs, over a year that decision could mean depositing 500 lb less weld metal. Depending on labor/overhead rates, that welder's decision could mean over $8,000 extra cost per year.

Overwelding. Fillet welds require no groove preparation and are one of the most commonly used weld types. Overwelding the required leg size by 1/16” may not sound like much. However, making a 5/16” fillet weld versus the required 1/4” fillet weld, can increase the weight of weld metal per foot of weld by 55%. Combined with the 55% increase in labor required to overweld by 1/16”, this decision can add almost $1 of extra cost per foot of weld.

Gas Leaks. Shielding gas is a high-cost consumable for GMAW (MIG) shops. Because most shielding gases are colorless and odorless, leaks are difficult to detect. By comparing gas consumption rate to actual weld time in a shop, leakage can be identified. One leak at 60cfh, at an average cost of $3.75/cf, can cost a shop over $20,000/year. Here are some easy, helpful controls/practices:

• Close gas bottle valves when not in use. Even when the connections and hoses between the bottle and the welding gun are tight and fairly leak-free, a bottle of gas can be drained over a weekend if left on! This is especially the case for expensive, helium-based shielding gas bottles.

• Installing devices to reduce gas delivery pressure to the wire feeder solenoid, and locking flow rates to proper levels can produce excellent savings. This will control gas usage at each welding station and reduce gas surges at the start of a weld.

• Identify and fix leaks on gas hoses and plant-wide gas distribution systems. Many times these leaks can be identified by listening for them in the quiet time after the shop is shut down. Otherwise, soap-bubble testing the gas distribution system from the gas source to every welding station can pay large dividends.

These controls take extra time to implement and manage, but they will help you survive these economic times and make you even more competitive when the good times return.

Q: Many companies have been switching from type 304 to type 201 stainless steel due to lower alloy surcharges. We are experienced in welding 304 stainless. Is welding 201 any different?

A: The 300 and 200 series stainless steels are both austenitic grades. The 300 series are Cr-Ni alloyed, while the 200 series are Cr-Ni-Mn alloyed. 200 series stainless is attractive due to its lower and more stable cost, primarily due to its lower Nickel content.

Type 201 offers comparable corrosion performance and higher strength than 304, while containing approximately half the amount of Nickel (Table 1). Manganese is added to partially replace the Nickel, in a 2:1 ratio. Manganese stabilizes the austenitic phase like Nickel, but is not as potent.

Type 201 stainless may be welded with 209, 219, or 308 filler metals. However, 200 series filler metals aren't used as widely as 308. Conventional procedures and techniques used for welding the 300 series apply to the 200 series, too.

Ken Lee, Application Engineer at Lincoln Electric Co., is a Certified Welding Engineer who has been with Lincoln Electric for 19 years. Kevin Beardsey, Application Engineer at Lincoln Electric, is a registered Professional Engineer with 21 years of manufacturing experience. Send your questions to Ken and Kevin by e-mail to: AskKenKevin@penton.com.