County and city bid documents for grader blades are written in metallurgy shorthand. This cheat sheet translates every common spec term into plain English — so you can verify a quoted product actually matches the bid before you buy (or before you award).
| Spec term / language | What it means | What to look for when ordering |
|---|---|---|
| Brinell Hardness Number (BHN or HB) e.g., “400–450 HB” or “500 BHN min” | A standard measure of how hard (wear-resistant) the steel is. Tested by pressing a steel ball into the surface and measuring the indentation. Higher number = harder steel = longer wear life. | 400 HB minimum for general grading; 500 HB for high-wear routes. A blade rated “400–500 BHN” is standard through-hardened steel. “500 BHN min” means premium abrasion-resistant (AR) grade. Anything below 350 HB is mild steel — avoid for grading work. |
| ASTM A514 / AR400 / AR500 | ASTM A514 is a high-strength, low-alloy quenched-and-tempered steel specification. AR400 and AR500 are trade-name grades of abrasion-resistant steel targeting 400 and 500 Brinell hardness respectively. | If a spec calls for ASTM A514 or equivalent AR400/AR500, the blade must be made from properly heat-treated alloy steel. AR500 is harder and longer-lasting; AR400 balances toughness with wear resistance. |
| Heat-treated / Through-hardened | The blade is hardened all the way through its thickness (not just surface-hardened). The entire cross-section reaches the specified hardness rating during manufacturing. | Blades described as “through-hardened to 400–500 BHN” or “heat-treated alloy steel.” This is the baseline quality requirement in most government bids. Surface-only hardening or mild steel is not compliant. |
| Carbide-tipped / Carbide-insert | Tungsten carbide — an extremely hard wear material — is inserted into grooves or welded/brazed onto the cutting face. Carbide is far harder than any steel grade. | Bids specifying carbide edges usually require a minimum number, size, and placement of inserts. Verify the carbide grade (e.g., C2, C3) if listed. Appropriate for high-abrasion routes; required in some DOT/county specs. |
| Curved / Crown | The blade has an arc along its height from top edge to cutting edge, rather than being a flat plate. Sometimes called a “crowned” edge. | “Curved” or “crowned” indicates a blade designed to roll material forward while grading. Confirm curved blades are compatible with the moldboard — flat and curved are not interchangeable on many machines. |
| Double-bevel | Both front and back edges of the cutting face are beveled, so when one edge wears down the blade can be flipped 180° to expose a fresh cutting edge. | “Double-bevel reversible” means the blade must be usable in two orientations — a common government requirement for value. Verify the bevel angle if specified (common: 30°–45°). |
| Bolt-on reversible | The blade attaches to the moldboard with bolts (not welded) and can be unbolted, flipped, and re-installed to use the unworn edge — doubling usable wear life. | Standard plow-bolt attachment with countersunk square holes. Confirm bolt size (common: 3/4” plow bolts) and that the blade can physically be reversed on the moldboard. Most bids require bolt-on designs. |
| Punched / Drilled pattern e.g., “punched 11/16” sq. holes on 6” centers” | The bolt holes are punched (stamped under press) or drilled. Hole size and center-to-center spacing must match the grader moldboard exactly. | Hole size (e.g., 11/16” or 13/16” square), spacing (6” centers is a common standard), and total hole count. A mismatch means the blade won't fit — always cross-reference the grader make/model in the bid. |
| Gauge / Thickness e.g., “5/8” thick”, “3/4” thick”, “18 mm” | The thickness of the blade measured straight through the steel, not counting bevel. Thicker blades provide more wear material. | Most county bids specify 5/8” (≈16 mm) or 3/4” (≈19 mm) minimum. Thicker costs more but reduces replacement frequency. Verify tolerance if stated (e.g., ±1/16”). |
| Width (blade height) e.g., “6” wide”, “8” wide” | The measurement from top mounting edge to bottom cutting edge — called “width” in catalogs though it's the vertical height when installed. | Common widths: 6”, 8”, 10”. Must match the moldboard channel depth. Width is not the same as blade length. |
| Length e.g., “84” long”, “12 ft blade” | Total end-to-end measurement. Blades are ordered full-length or in shorter segments that together span the moldboard. | Must match the moldboard size. Common lengths: 84” (7 ft), 96” (8 ft), 120” (10 ft), 144” (12 ft). Multi-piece setups bolt end-to-end. |
| AASHO-modified (older specs) | AASHO (now AASHTO) developed early standards for grader-blade bolt patterns on public road equipment. “AASHO-modified” refers to a historical punch-pattern standard with square countersunk holes. | In older bids this means a specific hole size/spacing pattern. Modern bids list exact dimensions directly — confirm with the issuing agency whether current industry-standard patterns are acceptable. |
We supply heat-treated and carbide motor-grader blades in bulk to Texas counties and municipalities — bid-spec compliant, delivered. Send your spec sheet or old-blade measurements and we'll quote it fast.
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