Specifications include, but are not limited to: Element Percent Carbon 0.80 - 1.00 Manganese 0.60 - 1.00 Phosphorous Maximum of 0.04 Sulphur Maximum of 0.05 Silicon Maximum of 0.30 The Brinell Hardness shall be between 240 and 325 ; The cutting edges shall be fabricated from hot rolled carbon steel bars meeting requirements within the range of SAE 1020 to SAE 1045. The fabricator shall indicate in his bid the grade of steel that he will use. 2.2.1.1 Shape and Dimensions: The cutting edges shall be 3/4" X 6" flat steel bars 36" or 48" in length. Length tolerances shall be : Plus "0" and minus 1/8". 2.2.2 Tungsten-Carbide Inserts: The Tungsten-Carbide inserts shall meet the following requirements: 2.2.2.1 Chemical and Physical Properties: Cobalt (percent) 10 - 13 Specific Gravity 14.0 Minimum Rockwell "A" Hardness 87 Minimum ; The inserts shall be trapezoidal in shape as shown on attached drawing, and with the following dimensional tolerances for trapezoidal shape: Height - 0.625" + 0.010 (long side) Thickness - 0.375" + 0.010 Length - 1" Nominal The rear edge of the blade must be beveled to the same angle as the insert or cut square with the short side of the insert.