attachment-2-bid-128-26-specs.pdf

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 1 of 6

Mark Kirouac, Assistant State Maintenance Engineer Bureau of Highway Maintenance New Hampshire Department of Transportation

FLEXIBLE PLOW BLADE SPECIFICATIONS

Note: All shop drawings for nose pieces, plow blades, adaptor blade kits, and curb runners/plow blade guards are to be reviewed by NHDOT Highway Maintenance prior to manufacture.

Special Note Regarding Carbide Inserts and Rubber Molding around Carbides: To ensure compliance with our specification, all bidders must submit with their bid, a Certificate of Analysis for the carbide inserts and rubber matrix/molding to be used in the manufacture of the blades. A random sample will be selected AFTER delivery for testing to ensure compliance on both these items.

All left and right hand terminology used in this specification is relative to a driver sitting in a truck.

Plow Edge General Specifications

The plow edge blade shall consist of individual steel segments encased in rubber with steel bushings positioned on 12" centers for mounting to the plow. Each segment shall be milled to a special shape and profile and inserted with tungsten carbide bits, brazed in place along the wear edge.

Finished Specifications

The finished blade shall be approximately 7/8" thick by 6" wide weighing 9.75 lbs. per foot.

11/16" ID steel bushings shall be located 1.5" from the top of the blade on 12" centers to facilitate mounting to the plow. Each blade shall have blade orientation embossed in the rubber casing.

A 1/2" x 3" heat-treated 15B30 clamp bar shall be mounted on top of the plow blade to hold the blade on the plow. This clamp bar weighs approximately 5 lbs. per foot and has 11/16" square holes located on 12" centers to align with the bushings in the blade and shall be a part of the plow edge.

Complete nut and bolt sets shall be provided with each plow edge.

Steel Segment

1. Cast steel 0.75” thick by 5” wide and 11.22” long.

2. The top 3.125” of the segment shall be milled down to 0.625” thick.

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 2 of 6

3. The lower, inserted section shall remain 0.75” thick. Slots measuring 8.2 mm wide x

24.5 mm deep shall be milled in this portion to receive tungsten carbide inserts and braze matrix.

4. The segment shall be cast to a ‘horseshoe’ design. The upper ears shall measure 2.55” wide (each with a 0.50” x 2.00” clip on the outside edges). The cutout measures shall be 6.13” x 2.8125” with 1” rads in the two lower corners

Tungsten Carbide Inserts

1. High shock resistant grade tungsten carbide.

2. Rooftop shape shall measure approximately 8.16mm thick, 24.25 mm tall and 25.9mm long.

3. Each insert shall weigh approximately 69 grams.

4. Each finished segment shall have 11 inserts (approximately 759 total grams of carbide insert material).

5. Tungsten carbide shall be 89% by physical weight – 100% virgin materials

6. Specific gravity shall be 14.35 to 14.6.

7. Hardness shall be 87.5 – 88.8 Rockwell A

8. Transverse rupture strength shall be 351,000 – 428,000 psi.

Braze

1. Inserts shall be brazed on all sides using Nickel/Silver braze

2. Shear strength shall be approximately 70,000 psi.

3. Maximum height difference between highest and lowest inserts shall be 1/32” in each 11.22” segment

4. Braze Composition Shall Be:

Copper/Silver 46.0-50.0%

Silicone 0.04-0.25%

Nickel 9.0-11.0%

Phosphorus 0.25%

Aluminum 0.01%

Lead 0.05%

Zinc Remainder

Rubber Matrix

1. Typical Physical Properties Shall Be:

Ultimate Elongation 582%

100% Modulus 276 psi.

Tensile Strength 3113 psi.

Shore A Durometer 60 pts.

Tear Strength 341 psi.

Compression Set 26.5%

Brittleness No cracks at –40C

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 3 of 6

Adapter Blade Blade

1. Blade shall be ASTM A36 Structural Grade hot rolled flat steel. Blade size is 3/4" x 7” x 3

ft. or 4 ft. long.

2. Blade to have (2) sets of holes. The top set is a 2” on center punch pattern with holes drilled, counter-sunk, and square punched to accommodate a 5/8" plow bolt. The bottom set of holes has a 3-3-12 punch pattern, and are drilled thru at 11/16" diameter.

3. Dimensional tolerance between hole spacing is +/- 1/16" (non-accumulative) from center to center across the full length of blade.

4. The milled channel for carbide insert retention shall be positioned in the center of the blade edge.

5. Each blade will have weld stops positioned to enhance the performance of the blade assemblies.

6. All blades shall have a durable and clearly visible wear line in order to easily determine when blades need to be changed.

Carbide Inserts

1. Inserts shall be trapezoidal in design, with the following dimensions:

a. Length: 1.0" nominal

b. Width: 0.36" min.

e. Height: 0.63" max.

d. Top angle: 25° with nose radius of 0.06"

2. Inserts to contain 89% tungsten (average by weight) and shall be of a grade containing 11% cobalt (average by weight).

3. Specific gravity (density) shall be between 14.35 and 14.60 gm/cc.

4. Hardness shall be Ra scale between 87.5 and 88.8, and have a minimum traverse rupture strength of 351,000 psi.

Brazing

1. Each blade shall contain approximately (1) 1” carbide insert for each 1” of blade length.

2. The carbide inserts shall be placed in-line within the milled channel.

3. The carbide inserts shall be brazed on all sides in contact with the blade using sound brazing practice, having no evidence of voids, and no use of shims or fillers.

4. Brazing material shall have a tensile strength of 70,000 psi.

Finished Product

1. Carbide tip points shall not exceed 1/32" between the highest and lowest point within any blade.

2. Finished blade will receive a complete powder coat (black) process for rust prevention.

Front face of blade will be identified for proper installation.

3. Finished product will comply with standard blade manufacturing tolerances.

4. Manufacturer's literature and assembly instructions shall be furnished with each kit.

5. Complete plow set-up will consist of a combination of (3) blade sections as per the chart below and each be packaged individually as a kit with assembly instruction.

6. Complete nut, conical washer and bolt sets shall be provided with adapter blades

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 4 of 6

10’ FRONT ADAPTOR BLADE PLOW SETUP KIT

QTY Description

2 ¾” x 7” x 36” Carbide Adaptor Blade

2 7/8” x 6” x 36” Blade

2 3 Ft. Strap

1 ¾” x 7” x 48” Carbide Adaptor Blade

1 7/8” x 6” x 48” Blade

1 4 Ft. Strap

1 6” Left Curb Runner for Blade

1 6” Right Curb Runner for Blade

KIT shall include the following hardware packaged as a plow bolt kit:

(8) 5/8”- 11 x 4” Full Thread, Grade 8 Carriage Bolts

(6) 5/8”- 11 x 4” Grade 8 Plow Bolts

(18) 5/8”- 11 x 3” Grade 8 Plow Bolts

(32) 5/8”- 11 Grade 8 Stover Lock Nut

(32) 5/8” Conical Washers

11’ FRONT ADAPTOR BLADE PLOW SETUP KIT

QTY Description

1 ¾” x 7” x 36” Carbide Adaptor Blade

1 7/8” x 6” x 36” Blade

1 3 Ft. Strap

2 ¾” x 7” x 48” Carbide Adaptor Blade

2 7/8” x 6” x 48” Blade

2 4 Ft. Strap

1 6” Left Curb Runner for Blade

1 6” Right Curb Runner for Blade

KIT shall include the following hardware packaged as a plow bolt kit:

(8) 5/8”- 11 x 4” Full Thread, Grade 8 Carriage Bolts

(6) 5/8”- 11 x 4” Grade 8 Plow Bolts

(18) 5/8”- 11 x 3” Grade 8 Plow Bolts

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 5 of 6

12’ FRONT ADAPTOR BLADE PLOW SETUP KIT

QTY Description

3 ¾” x 7” x 48” Carbide Adaptor Blade

3 7/8” x 6” x 48” Blade

3 4 Ft. Strap

1 6” Left Curb Runner for Blade

1 6” Right Curb Runner for Blade

KIT shall include the following hardware packaged as a plow bolt kit:

(8) 5/8”- 11 x 4” Full Thread, Grade 8 Carriage Bolts

(6) 5/8”- 11 x 4” Grade 8 Plow Bolts

(18) 5/8”- 11 x 3” Grade 8 Plow Bolts

Flexible Plow Blade Specification – NH DOT 8/10/2022 Page 6 of 6

Curb Runner Guard- Left and Right

In addition to text below, please reference drawing of curb runner guard.

Steel 1060 Grade Steel or High impact, ASTM Grade A-36 or greater Hot Rolled bar stock, 3/4" thick.

Bolt Holes Drilled and square punched with countersink (3) places to accept 5/8" Plow Bolt flush with front mounting blade surface.

Rust Prevention Chip and corrosion resistant base paint on all surfaces. Bright Safety Orange paint over base paint in carbide matrix area.

Curb Runner Casting 1045 Grade Steel or A-22 Cast Steel material with (0.32-O.9 lbs.) of carbide matrix.

Part Identification Each curb runner guard has a label on the front mounting blade surface identifying the manufacturer and contact information.

Carbide Matrix Chemistry

Material Minimum Value

Carbon 4.0

Silicon 0.5

Chrome 25

High Temp Carbide Formers 0.5

Nitride Formers 0.5

FE Balance

Rockwell C Hardness 55-80

Painting – All Flexible Plow Blade Equipment

All surfaces which are normally painted shall be painted with coatings suitable for severe exposure to road salt and abrasion.

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Carbide Adaptor Blade - 36" 1/4/2022 NHDOT

Drawings are NOT to Scale (but generally close)

Basic Blank Measurement

3/4" x 7" x 36"

Top Set of Holes:

17 holes - square 11/16 thru - punched every 2" on center

82 degrees Countersunk, to 1-1/8" Diameter x 1/8" deep to accept 5/8-11 Plow Bolt

35-15/16"

2" 2"

2"

7"

2-1/2" 12" 12"

3" 3" 3" 3"

Bottom Holes

11/16" Diameter Through (5 holes)

Carbide Adaptor Blade - 48" Center Mounting 1/4/2022 NHDOT

Drawings are NOT to Scale

Basic Blank Measurement

3/4" x 7" x 48"

Top Set of Holes:

23 holes - square 11/16 thru punched every 2" on center

82 degrees Countersunk to 1-1/8" Diameter x 1/8" deep to accept 5/8-11 Plow Bolt

47-15/16"

2" 2"

2"

7"

2-1/2" 12" 12" 12"

3" 3" 3" 3"

11/16 Diameter Through (6 holes)

Carbide Adaptor Blade - 48" Center Mounting 1/4/2022 NHDOT

Drawings are NOT to Scale

Basic Blank Measurement

3/4" x 7" x 48"

Top Set of Holes:

23 holes - square 11/16 thru punched every 2" on center

82 degrees Countersunk to 1-1/8" Diameter x 1/8" deep to accept 5/8-11 Plow Bolt

48-15/16"

2" 2"

2"

7"

2-1/2" 12" 12" 12"

3" 3" 3" 3"

11/16 Diameter Through (6 holes)