12-point bolts are easier to assemble and eliminate the possibility of rounding of the head that commonly occurs with standard hex head cap screws. 12-point bolts also offer a lower profile head making them more aesthetically pleasing than standard hex head cap screws.
Twelve Point Flange Screws are an alternative head design for hex socket cap screws. The flange diameter and head height are designed to fit applications and counterbored holes designed for standard hex socket cap screws. The 12 point design permits greater torque to be applied to the bolt and eliminates the rounding of the hex socket that occurs with standard hex sockets.
ASTM A437/A437M Grade B4B alloy steel bolting material and bolting components are specially heat treated for high temperature service, such as steam turbine, gas turbine, and similar uses. The high-temperature properties of the bolting materials and components covered by this specification are dependent upon special heat treatment, which is required. Although the high-temperature properties are not specified, they are implied by control of the chemistry, heat treatment, and room-temperature properties of the bolting material. Three levels of bolting strength are covered, designated Grades B4B, B4C, and B4D. Hex Bolts, Turbine Bolts, Studs, Socket Head Cap Screws, Threaded Rods, Nuts & Washers can be manufactured from ¼” to 4” in imperial and M6 to M100 in metric variants both fine threads and coarse threads
TYPE OF STEEL - Martensitic stainless steel
OFFICIAL TEST CERTIFICATE - issued by TUV - SGS - BV
Technical standards - ASTM A437 - 2012
CHEMICAL COMPOSITION (WEIGHT %)
C (％): 0.20 ~ 0.25
Si (％): 0.20 ~ 0.50
Mn (％): 0.50 ~ 1.00
P (％)≤: 0.025
S (％)≤: 0.025
Cr (％): 11.0 ~ 12.5
Ni (％): 0.50 ~ 1.00
Mo (%): 0.90 ~ 1.25
W (%): 0.90 ~ 1.25
V (%): 0.20 ~ 0.30
Al (%): ≤ 0.05
Ti (%): ≤ 0.05
MECHANICAL PROPERTIES UNDER ROOM TEMPERATURE
Condition: Quenched 1025 ~ 1050℃, oil cooled
Tempered 650℃ min., air cooled
Annealed hardness: 321 max.
Tensile strength,σb/≥ MPa: 970
Yield strength, σ0.2/≥ MPa: 720
Elongation, δ ≥(％): 13.0
QT hardness: 352 max.
Impact, AKV: 14J min.
