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Strengthening Metal Parts with Hardfacing

27 April, 18 2:42 pm · Leave a comment · reddarc
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Metallic parts sometimes fail their intended use at a lower stress than they are designated for.
Various forms of wear such as abrasion, impact, metal to metal contact, heat, and corrosion can compromise the strength of metal pieces. This is where hardfacing comes in. Hardfacing is a technique which can be applied to minimize the damage from these types of wear, helping to prolong the life of metal pieces.

What is hardfacing?

Hardfacing —often called hardsurfacing— is the covering of the metallic part with a wear resistant metal by welding. Alloys which commonly need to be hardfaced include carbon alloy and low alloy steels whose carbon content is lower than 1 %. These include stainless steels, manganese steels, cast iron as well as nickel and copper-based alloys.

Metallic parts sometimes fail their intended use at a lower stress than they are designated for.

Techniques, Materials and Costs

The particular hardfacing technique for a job depends on the geometry of the part and relative cost of the hardfacing method. Costs can vary with the deposition rate of the material.

These cost variations can be summarized as follows:

  • Flux cored arc welding (FCAW) 8 to 25 lb/hr
  • Shielded Metal Arc Welding (SMAW) 3 to 5 lb/hr
  • Gas Metal Arc Welding (GMAW), including both gas-shielded and open arc welding 5 to 12 lb/hr
  • Oxyfuel Welding (OFW) 5 to 10 lb/hr

 

Applied materials commonly include cobalt based alloys such as STELITE, and nickel based materials like chromium carbide alloys. More advanced materials such as complex carbides containing columbium, molybdenum, tungsten, or vanadium can also be used and provide more overall abrasion resistance. They also have a very low friction factor, which can be used in situations involving severe abrasion.

Hardfacing can be applied to both newly manufactured pieces, in order to prevent deterioration, or to strengthen and extend the life of worn pieces currently in use.

Red-D-Arc provides welding machines suitable for hardfacing using techniques including SMAW, FCAW and GMAW.

The Importance of Welding Surface Preparation

28 March, 18 2:08 pm · Leave a comment · reddarc
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By guest blogger David H.

welding surface preparationHaving worked in shipyards for seven years, I’m familiar with how dirty this type of job site can be. Ship repair worksites and welding surfaces are often filthy with rust, dust and other contaminants. Even in shops and yards where fabrication is ongoing, cleanliness is often lacking. If fabricated or refurbished pieces are being installed onboard, the surface to which the piece will be welded could be rusty, coated with scale, or have other types of corrosion.

It is hard to overstate the importance of having a clean surface when welding. Welds made on unclean surfaces can become contaminated and fail; this is especially true with certain metals, such as aluminum, and certain types of welding, such as TIG, but for all welds at least some level of cleanliness is important.

Methods and Equipment

There are numerous methods available for cleaning surfaces. The most basic are simple wire brushes and scrapers; these are ineffective beyond removing common dirt and simple surface contamination. Some hand-held tools, such as grinders and reciprocating needles are slightly more effective.

A surface that is properly prepared by blast cleaning can help you ensure fewer problems with weld quality.

Deeper cleaning processes can help to ensure high-quality welds. This is particularly important where a failed weld could be costly or create shipboard dangers for the crew. For corroded or contaminated surfaces something stronger is required. Some of the best systems available are blast cleaners. Red-D-Arc has a number of blast cleaning rental options. Dry-ice systems are environmentally sustainable, non-destructive, and use inexpensive, readily available dry-ice pellets. Recycled glass systems, which reduce dust by as much as 95% compared to dry-blasting, are available too.

Take a look at our selection of  rental blast cleaners which can powerfully clean up the dirtiest weld surface. A surface that is properly prepared by blast cleaning can help you ensure fewer problems with weld quality.

Fast, Efficient Flux-Cored Welding with Semi-Automatic Wirefeeders

29 January, 18 2:43 pm · Leave a comment · reddarc
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Flux cored welding with semi-automatic wirefeedersBy guest blogger David H.

Some years back I was working in a shipyard in San Francisco. The yard had several small repair jobs going, plus a fairly large project building six ocean-going barges. The supervisor who was in charge of the barge-building project was looking for volunteers to operate semi-automatic wire feeders, using flux-cored wire, to weld stiffeners to the skin of the barges. I had never used a wire feeder before, so I volunteered out of curiosity.

After a very short training period, possibly all of 30 minutes but I think a bit less, I was off and running. I was impressed by the quality of the welds and the speed at which they were deposited. Without question I was outpacing anything that could be done by stick welding, and I felt it was easier to maintain a uniform weld size too. The machine itself was light enough and small enough to move without difficulty, and the spools of wire lasted long and were quick and easy to replace when the spool of welding wire was finished.

Red-D-Arc has nearly a dozen semi-automatic wire feeders available for almost any application. We also carry fully automatic wire feeders, which are faster still and appropriate in certain circumstances – like building storage tanks –  especially for large-deposition welds.

Stainless Steel Welding: Details That Matter

14 November, 17 2:46 pm · Leave a comment · reddarc
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drilling platformBy guest Blogger Katarzyna K.

Katarzyna has an Msc in Materials Science and has worked in the oil and gas industry in jobs related to hydraulics, welding and the retrofitting of oil rigs.

Stainless steel is used extensively in the petrochemical industry due to its high resistance to severe conditions. When welding inox steels, the smallest details matter and have an impact on weld quality. The following are some tips for stainless steel pipe welding based on my oil rig repair experience:

During an oil rig repair project that involved 2205 duplex stainless steel pipe TIG welding, we could not achieve the required weld properties. Despite using the recommended filler metal with higher nickel content, compared to the base metal, and controlling the interpass temperature, the weld tensile strength was still too low. In order to reach the required weld quality we dug deeper and found a solution – (more…)

Submerged Arc Systems Increase Productivity by 250%

28 October, 17 1:49 pm · Leave a comment · Taylor Stewart
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A metal fabrication company located in Charlotte, North Carolina received an order for 300 small I.D. vessels for titanium molds. At the time they were using FCAW and back gouging the inside and outside of the vessels to achieve 100% penetration. On average they were producing 2 vessels per hour with 2 welders.

They reached out to Red-D-Arc to find a faster and more efficient way to produce these vessels. After discussions with Red-D-Arc the fabricator decided to purchase a turnkey submerged arc system. The custom designed system came complete with a small I.D. sub arc welding head mounted on a 9’x9′ manipulator, flux recovery system, NA5R automatic wire feeder, DC600 multi-process welderand 5 ton turning rolls. The system also included a laser and camera for precise control and monitoring of the submerged arc welding process.

The submerged arc system increased productivity by 250%. They were able to produce 5 cans per hour with half the labor cost. The safety of the work place was also significantly increased for a number of reasons:
• Back gouging was eliminated which in turn reduced the risk of fire
• Turning rolls replaced manual rotation of the vessels on tables
• Welders no longer had to weld inside the confined space of the vessels

The customer and the Red-D-Arc team were beyond pleased with the results. The customer plans to purchase two more of these systems for future projects.

Submerged arc welding can increase the efficiency and quality of many industrial welding projects regardless of the size or complexity. Red-D-Arc has all the equipment, expertise and experience to provide you with a submerged arc system to fit your needs – available for sale, lease and rent

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