Accession Number : ADA289127

Title :   Improved Hardness RHA Weldability and Material Property Testing.

Descriptive Note : Final draft Technical rept. Aug 91-Jun 94,

Corporate Author : GENERAL DYNAMICS CORP WARREN MI LAND SYSTEMS DIV

Personal Author(s) : Foos, Michael L.

PDF Url : ADA289127

Report Date : DEC 1994

Pagination or Media Count : 126

Abstract : The M1-PMO, in conjunction with the US Army Research Laboratory (ARL) would like to potentially up-armor the M1 family of vehicles by increasing the hardness of rolled homogeneous armor (RHA) MIL-A-12560 steel. The basic thrust of the program is to utilize lower tempering temperatures and chemist of slightly more hardenability to produce a RHA armor with a Rockwell 'C' hardness of 39-48 without altering the current specification MlL-A-12560 steel. It is believed that the increased hardness levels will provide increased ballistic protection against large caliber kinetic energy threats. Weldability and material property tests were performed on the improved hardness RHA steel supply by the US ARL. The program involves basic material characterization, weldability, machinability and plate cutting studies. The material characterization was performed on two thicknesses (1.25' and 1.50'). The weldability study included Y-groove preheat testing, stud welding and maximum heat input testing. The machinability testing involved machining parts including drilling, tapping, reaming, boring and milling. Plasma and Oxy-fuel thermal cutting were studied to gauge processing of the steel by present armor vehicle fabrication. The ballistic testing was performed by US Combat Systems Test Activity (CSTA) at Aberdeen MD. The results show the candidate steel can processed typical to RHA steel with minor impact to welding and machining.

Descriptors :   *ARMOR, *STEEL, *HARDNESS, *HOMOGENEITY, TEST AND EVALUATION, INPUT, THICKNESS, LOW TEMPERATURE, ARMY RESEARCH, IMPACT, MACHINING, WEAPON SYSTEMS, MATERIALS, PROCESSING, TEST METHODS, FABRICATION, KINETIC ENERGY, LEVEL(QUANTITY), PROTECTION, PARTS, SUPPLIES, HEAT, BALLISTICS, THRUST, TEMPERING, GAGES, ARMORED VEHICLES, MACHINABILITY, ROLLING(METALLURGY), STUD WELDING, WELDING.

Subject Categories : Metallurgy and Metallography
      Armor
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE