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Figure 1 Bohler Cladding Head Demonstrating Electroslag Strip Cladding
Figure 2 Electroslag Strip Cladding Deposits made using 60 mm Stainless Steel Strip
Figure 3 Submerged Arc Strip Cladding Deposits made using 60 mm Stainless Steel Strip

Addition of Cladding Equipment for Surface Engineering

Ian Harris | Technology Leader, Arc Welding

EWI has added new surface engineering capability thanks to an equipment consignment by Bohler Welding Group USA LLC. Bohler recently consigned a cladding head for strip cladding using 30- and 60-mm strip (Figure 1). The equipment is capable of both electroslag strip cladding (ESSC) with welding current up to 2000 A (Figure 2) and submerged arc strip cladding (SASC) (Figure 3). While SASC and ESSC are established processes, the ability to clad with ESSC at power levels of up to 2000 A, and deposition rates up to 70 lb/hr, is relatively new. This equipment compliments a wide array of hardfacing and cladding processes already available at EWI for developing wear, corrosion, and other surface engineering application solutions; namely: GTAW (hot and cold wire), PTA (wire and powder), SAW, FCAW, GMAW-P, GMAW-MP. A comparison of typical deposit thickness, deposition rate, and dilution for each process is summarized below.

Process
Min. Deposit Thickness (in.)
Deposition Rate (lb/hr)
1st Layer Dilution (%)
Electroslag Strip Cladding
0.160
30-70
5-20
Submerged Arc Strip Cladding
0.160
20-50
10-25
Gas Tungsten Arc Welding - cold wire
0.060
3-4
5-10
Gas Tungsten Arc Welding -
hot wire
0.080
4-12
5-10
Plasma Transferred Arc
0.080
4-20
2-10
Submerged Arc Welding
0.125
20-40
15-30
Flux Cored Arc Welding
0.080
6-12
15-30
Pulsed Gas Metal Arc Welding
0.080
6-12
10-30
Mechanically-Pulsed Gas Metal Arc Welding
0.060
2-5
1-5

The deposition rate for the strip cladding processes is very high, offering potential to significantly increase productivity for suitable cladding applications. As seen in Figures 2 and 3, slag release for both SASC and ESSC is very good and deposit quality and surface appearance is also up to requirements of demanding applications for heavy fabrication. Typical applications in industry include cladding of rolls and shafts, and cladding of large vessels and pipes. In addition to surface engineering using welding processes, EWI also possesses thermal spray coating processes that compete with weld overlay coatings for solutions to wear and corrosion issues. Thermal spray coating processes available include high velocity oxyfuel and twin wire electric arc spraying. EWI will be investigating novel applications for ESSC and SASC for a range of alloys, with focus predominantly on various grades of stainless steels and nickel based alloys. Full metallurgical, corrosion, and wear characterization can be conducted in support of application development. This equipment will be demonstrated during an EWI sponsored Surface Engineering Seminar planned for April 2010 in Columbus and is available immediately for application development.

For additional information, contact Ian Harris at: iharris@ewi.org or call 614.688.5131.