Verification lots were needed to ascertain that problems with the manufacturing process and testing methods for the MIL-10718-M electrode have been corrected.
For CVN 78, the MIL-10718-M electrode must be used for all shielded metal arc welding (SMAW) of High-Strength Low-Alloy Steel (HSLA-100) and High Yield Strength (HY-100) steels to meet the required ballistic performance. However, the electrode is only available in a 1/8 inch diameter size, which has a history of unacceptable rejection rates during conformance and/or in-house verification testing at Northrop Gruman Shipbuilding-Newport News (NGSB-NN). After extensive work on the rejection causes, Naval Sea Systems Command (NAVSEA) made revisions to the material to meet the needs of both NGSB-NN and General Dynamics Electric Boat (EB), the systems integrator for the Virginia-class submarine.
This project optimized 1/8 inch diameter and developed 3/32 inch diameter MIL-10718-M SMAW electrodes, thus providing two diameters of MIL-10718-M electrodes that consistently meet the required ballistic performance in welded HSLA-100 and HY-100 steels. NMC worked with two electrode manufacturers to optimize MIL-10718-M manufacturing and tested practices for the two electrode diameters. The electrode manufacturers will provide multiple lots of each size electrode to NGSB-N and EB for verification of operating characteristics, weld metal mechanical properties and welder appeal.
The project achieved consistent performance with three lots each of 1/8-inch and 3/32-inch MIL-10718-M electrodes from ESAB and Lincoln. These electrodes will provide welds capable of consistently meeting required performance in welded HSLA-100 and HY-100 steels. The ability to procure these electrodes from two manufacturers allows for greater flexibility, provides competition in pricing and ensures consistent availability to the U.S. military and military contractors.
Both the improved 1/8-inch and new 3/32-inch MIL-10718-M electrodes have been approved for use in naval weapon systems. The 1/8-inch electrode was implemented on CVN 78 hull starting in January 2007 as well as on the Virginia Class Submarine (VCS). The 3/32-inch electrode has been approved for use on CVN 21 and VCS.
StakeholderLCDR Brian A. Metcalf