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Anchor Bolt

High Strength Anchor Bolt

Wind turbine anchor bolt raw material is 42CrMoA and other equivalent materials. It is purchased from large and qualified steel mills. Each steel round bar went through ultrasonic flaw detection before delivery. According to GB/T 4162 standard, reaches Class A level. AGICO guarantee high strength anchor bolts supplied can meet or even higher than the technical specifications required in bidding documents.

Our high strength anchor bolts for wind turbine are manufactured following strict standard production process: anchor bolt is heat treated and then threaded: anchor bolt is tested after heat treatment, then peeled and drawing is processed to the specified medium diameter size. Peeling process can remove oxide scale and decarburization layer generated during heat treatment; and the last is screw thread.

Note: The middle part of wind turbine anchor bolt is not machined, it is one-time forming and thread precision is better.

Patent for High Strength Anchor Bolt

High Strength Wind Turbine Anchor Bolt Production Process:

Production Process Flow

Purchase raw materials according to plan (designated steel mill materials and grades) → Raw material Inspection → rough straightening → heat treatment (medium frequency induction heat treatment) → inspection (performance test) → peeling and fine alignment (100% ultrasonic flaw detection, fluorescent magnetic particle inspection, etc.) →Unloading→Machining (Chamfering)→Coded→Thread Rolling→Inspection (Threading Precision Gauge, Medium Diameter Micrometer, etc.)→ Anchor Bolt Tension Detection→ Anchor Bolt Anticorrosion Treatment (Dakro, coated according to customer requirements) Grease + heat shrinkable tube, etc.) → inspection → packaging → storage.

  1. Raw material round bar rough straightening
  2. Heat treatment
  3. Peeling and fine alignment
  4. Chamfering
  5. Thread Rolling
  6. Anchor Bolt Anti-corrosion Treatment  

Inspection Equipment

Anchor Bolt Test after Production:

Tensile Test: We make 100% tensile test to steel bars according to client’s request, tensile strength is 70% of the yield strength.(A bit higher than actual tensile strength).The elongation or re-condensation within ≤±0.02mm/m.

Anti-Corrosion Test: We use anti-corrosion grease+anti-corrosion belt +PVC tube+sealing nut to achieve the purpose. After 1000 hours’ salt spray test, there will be no corrosion on the products’ surface.

Wind Anchor Cage Bolt Manufacture Equipment

Anchor Cage Bolt Assembly Parts:

Anti-Corrosion Treatment Anchor Bolt
Cap and Nut for Anchor Bolt

Dimension of Class 10.9 Anchor Bolt - AGICO

Anchor BOLT Grade 10.9
D Nom Diameter at smooth part Pitch Cross Section Yield force Ultimate force
mm mm mm mm2 KN KN
M36 33.23-33.29 4 817 768 735
M39 36.23-36.29 4 976 917 878
M42 38.90-38.96 4.5 1120 1052 1008
M48 44.56-44.63 5 1400 1381 1528
M56 52.22-52.30 5.5 2030 1908 2111

Dimension of Class 8.8 Anchor Bolt - AGICO

Anchor BOLT Grade 8.8
D Nom Diameter at smooth part Pitch Cross Section Yield force Ultimate force Weight/meter
mm mm mm mm2 KN KN kg/m2
M36 33.23-33.29 4 817 539 678 6.83
M39 36.23-36.29 4 976 644 810 8.12
M42 38.90-38.96 4.5 1120 739 929 9.34
M48 44.56-44.63 5 1470 970 1220 12.28

Mechanical Properties of Available Anchor Bolt Grades

Grade Dia Tensile Strength Rm/MPa 2% Elongation Limit RP 0.2/MPa Stress Under Proof Load SPf/MPa Elongation after fracture A/% Reduction oF Area after Fracture Z/% Rockwell Hardness /HRC Bolt Length mm -40 ℃ Impact Absorb Energy K/J
min max max
8.8 M16 ~M56 830 660 600 12 52 23 34 12000 27
9.8 900 720 650 10 48 28 37
10.9 1040 940 830 9 48 32 39
12.9 1220 1100 970 8 44 39 44

  Anchor bolt products have super high yield strength(up to 1100 MPa) and tensile strength(up tp 1220 MPa). Regarding impact energy, our grade 8.8 anchor bolt everages 60J , grade 10.9 everages 35J which means our products performance much higher than standard requirements.

Recognized Steel Grades for Anchor Cage Bolts

Anchor Bolt Steel Standard Steel Grade&Tensile Strength
ISO 4014 Grade 8.8
ASTM A615 / A615M Grade 75 (690 MPa [100 ksi] minimum tensile strength)
ASTM A722 / A722M (1035 MPa [150 ksi] minimum tensile strength)
ASTM A193 / A193M Grade B7 (860 MPa [125 ksi] minimum tensile strength)

Chemical Composition Comparsion of Anchor Cage Bolt Rod

CountryChemical Composition Comparsion of Anchor Cage Bolt Raw Material
Steel GradeCSiMnPSCrMo