Cold heading Service


Ningbo Teng Qi Fasteners Co., Ltd is a leading ASME B 18.2.1 hex bolts manufacturer in China. ASME B18.2.1 is a standard that specifies the dimensions, mechanical properties, and other relevant requirements for hexagon head bolts with unified thread pitch and thread lengths that are shorter than those of standard hex bolts. These shorter hex bolts are commonly used in applications where a shorter bolt length is needed.

The standard covers bolts made from various materials, including carbon steel, alloy steel, and stainless steel. ASME B18.2.1 hex bolts are used in a variety of applications, much like other hex bolts, but they are chosen specifically when the bolt’s length needs to be shorter while still maintaining the hexagon head and threaded design.

In summary, ASME B18.2.1 hex bolts offer standardized specifications for shorter hex bolts with unified thread pitch, ensuring interchangeability and reliability in various industries and applications.


Product nameASME B 18.2.1 HEX BOLT
LengthUp to 30"
Head TypeHex Head
GradeSAEJ429 GR.2/5/8
A307 A193 B7
Materialcarbon steel, stainless steel (304 or 316), alloy steel, brass, and more
Manufacturing Processwire drawing, cold heading/hot forging, thread rolling, heat treatment, surface treatment
Surface treatmentBlack Oxide Coating/Zinc Plating (Electroplating)/Hot-Dip Galvanizing/Mechanical Galvanizing/Dacromet Coating/Painting or Powder Coating
Application IndustryConstruction/Machinery/Automotive/Infrastructure/Electrical and Electronics/Furniture/Marine and Offshore

Chemical Composition:

GradeCarbon, %Phosphorus, %Manganese, %Sulfur, %
20.47 max0.120 max-0.15 max
50.55 max0.050 max0.30 min0.15 max
80.55 max0.040 max0.30 min0.05 max

 Mechanical properties:

GRADENominal Size, inchesFull Size Proofload, psiYield Strength, min, psiTensile Strength, min, psiElong, min, %RA, min, %Core Hardness, RockwellTempering Temperature, min
11/4 thru 1-1/233,00036,00060,0001835B7 to B100N/A
21/4 thru 3/45500057000740001835B80-B100N/A
Over 3/4 thru 1-1/233,00036,00060,0001835B70 to B100
51/4 thru 185,00092,000120,0001435C25 to C34800F
Over 1 thru 1-1/274,00081,000105,0001435C19 to C30
81/4 thru 1-1/2120,000130,000150,0001235C33 to C39800F
Grade 2 requirements for sizes 1/4" thru 3/4" apply only to bolts 6" and shorter, and to studs of all lengths. For bolts longer than 6", Grade 1 requirements shall apply.

Manufacturing Quality Control of ASME B18.2.1 Hex Bolts:

Control MethodDetail
Material Inspection:Verify the material's composition, heat treatment, and quality upon receipt. Conduct metallurgical analysis to ensure the material properties meet the standards.
Process Control:Implement strict process control measures for heat treatment, machining, threading, and any other manufacturing steps. Maintain consistent process parameters to ensure uniform quality.
Inspection Points:Introduce inspection points at various stages of manufacturing to check for defects, dimensions, and quality. Inspect threading, dimensions, surface finish, and other critical parameters.
Sampling and Testing:Regularly sample products for testing, such as tensile testing, hardness testing, and metallurgical analysis, to ensure they meet the required specifications.
Thread Inspection:Thoroughly inspect threading using proper thread gauges to ensure accurate dimensions and fit with mating components.
Traceability:Implement a traceability system to track each fasteners journey from raw material to final product. This aids in accountability and recalls if necessary.