Specifications include, but are not limited to: Special Note Regarding Carbide Inserts: To ensure compliance with our specification, all bidders must submit with their bid, a Certificate of Analysis for the carbide inserts to be used in the manufacture of the blades. A random sample will be selected after delivery for metallurgical testing for compliance. NEW HAMPSHIRE DEPARTMENT OF TRANSPORTATION SPECIFICATION TUNGSTEN CARBIDE TIPPED SNOW PLOW BLADES 1.0 BLADE 1.1 Blades shall be flat hot-rolled finished steel SAE 1020 of domestic manufacture. 1.2 Punching shall be 11/16" square holes to receive 5/8" diameter carriage bolts. Location and spacing of the holes shall be as shown on the attached drawings. 1.3 The groove for the carbide inserts shall be milled in the center of the blade edge. 1.4 Center of holes shall be in line within 1/32" of established centerline. 2.0 TUNGSTEN CARBIDE INSERTS 2.1 The inserts shall be WC grade of tungsten carbide with 11% to 12% cobalt content. Density: 14.1 minimum to 14.6 maximum. Hardness: 87.5 minimum to 89.0 maximum Rockwell "A" Scale. Transverse Rupture Strength (P.S.I.): 350,000 minimum. Porosity: (ASTM B276-79) A 06 B 00 C 00 2.2 Insert Design. The inserts shall be trapezoidal in shape to the following dimensions: Height: .750 + .005 (Long side) Width: .365 + .010 Length: 1 in. nominal Bottom Angle: 25 degrees with a nose radius of 1/16" minimum. 2.3 A metallurgical evaluation of the carbide insert shall show no evidence of cross grade contamination. Evaluation to be based on a photo micrograph of a polished and etched specimen at 500X magnification.
