Novel Steel Combat Helmet and Method of Production Thereof

Abstract

The invention relates to helmets designed to protect their wearers from ballistic impacts and shrapnel. Such helmets are well-known, and are the current standard for law enforcement and military use alike. Whereas such helmets used to be made solely of steel, combat helmets are today manufactured primarily from polymer composites such as aramid and ultra-high molecular weight polyethylene, and metal helmets have been largely superseded in common use, if not considered entirely obsolete, since the 1980s. The present invention, described herein, allows for the production of a modern steel helmet which is lightweight and exhibits excellent ballistic performance—performance which is comparable if not superior to that exhibited by the best polymer composite helmets of our day.

What is claimed is: 
     
         1 . A method for manufacturing a high-strength ballistic-resistant steel helmet shell, comprising the steps of:
 a) Preparing a steel blank by punching or cutting a steel plate, a steel sheet, or a section bar to appropriate dimensions.   b) Pre-treating the blank by austenitization or cold-drawing followed by austenitization.   c) Forming the helmet shell by pressing the heated and austenitized pre-form in a die. Once the draw depth is reached the part is hardened in the die by targeted cooling.   d) Finishing the forming process by tempering and quenching, to whatever extent necessary for optimal ballistic resistance, and then trimming the formed blank to its final shape.   e) Subjecting the exterior of the helmet shell to shot peening, severe shot peening (SSP), surface mechanical attrition treatment (SMAT), or ultrasonic nanocrystalline surface modification (UNSM), to induce the formation of a hard nanocrystalline surface layer, to whatever extent necessary for the degree of ballistic resistance required.   
     
     
         2 . A steel helmet shell, produced via hot stamping, press hardening, hydroforming, stamping, stretch forming, or super-plastic forming, wherein the finished shell is greater than 1.6 mm in thickness, and wherein the alloy contains >0.20% Al or Si, and more than 0.5% but less than 3% Mn, in addition to >0.18% carbon and other alloying elements, and wherein the finished helmet shell has a tensile strength over 1400 MPa. 
     
     
         3 . The steel helmet shell of  claims 1  and  2 , wherein the exterior surface of the shell is coated with an hard corrosion-resistant ceramic material via physical vapor deposition, chemical vapor deposition, thermal spray, or cold spray. 
     
     
         4 . A steel combat helmet comprised of the steel shell of  claim 1  or  2 , a harness, a padding system, and optional points for the attachment of accessories, wherein the stand-off distance between the shell and the wearer's skull is less than 16 mm, and wherein the helmet is nevertheless compliant with the NIJ Standard 0106.01, “Ballistic Helmets,” Type II.