Threaded Bolts - Stress Area
Threaded bolts tensile stress area.
The weakest points in a bolt is the stressed area in the thread root. The stressed area depends on the type of threads - coarse threads reduces the stressed area compared to fine threads.
UN and UNR Bolts Tensile Stress Area
The stressed area in a bolt can be calculated as
A = (π / 4) (dn - 0.9743/ n)2 (1)
where
A = stressed area (in2)
dn = nominal bolt diameter (in)
n = 1 / p = number of threads per inch
p = pitch, length per thread (in)
Despite that a reduced area will reduce the breaking load of a bolt - coarse threads are used for clamping. Fine threads bolts are weaker due to the reduced thread height.
ISO 898 Bolts Tensile Stress Area
Tensile stress area in bolts according ISO 898-1 Mechanical properties of fasteners made of carbon steel and alloy steel:
As,nom = (π / 4) ((d2 + d3)/ 2)2 (2)
where
As,nom = nominal stress area (m, mm2)
d2 = the basic pitch diameter of the external thread according ISO 724 ISO general-purpose metric screw threads -- Basic dimensions (m, mm)
d3 = d1 - H / 6 = the minor diameter of external tread (m, mm)
d1 = the basic minor diameter of external thread according ISO 724
H = the height of the fundamental triangle of the thread according ISO 68-1 ISO general purpose screw threads (m, mm)
Related Topics
-
Fasteners
Bolts, nuts and threaded rods - torque, tension and loads. -
Miscellaneous
Engineering related topics like Beaufort Wind Scale, CE-marking, drawing standards and more.
Related Documents
-
Bolt Stretching and Tensile Stress
Tensile stress and Hooke's Law. -
Bolt Torque Calculator
Calculate required bolt torque. -
ISO 724 - Metric Threads
Dimensions of metric threads according ISO 724. -
Metric Bolt Heads and Wrench Sizes
ANSI/SO, DIN and JIS bolts. -
Metric Bolts - Minimum Ultimate Tensile and Proof Loads
Minimum ultimate tensile and proof loads for metric bolts with coarse or fine threads. -
Metric Bolts - Tightening Torques
Recommended thightening torque metric bolts. -
Metric Steel Bolts - Grades and Property Classes
Metric steel bolts, screws and studs - proof and tensile strength. -
Reduced Torque with Lubricated Bolts
Lubrication effect on bolt tension and torque. -
Steel Bolts - ASTM Grades
ASTM steel bolts - proof and tensile strength. -
Steel Bolts - SAE Grades
SAE steel bolts - grades ranging grade 1 to 8.2 - proof and tensile strength. -
Steels - Endurance Limits and Fatigue Stress
Endurance limits and fatigue stress for steels. -
Stress
Stress is force applied on cross-sectional area. -
Stress, Strain and Young's Modulus
Stress is force per unit area - strain is the deformation of a solid due to stress. -
Thermoplastics - Physical Properties
Physical properties of thermoplastics like ABS, PVC, CPVC, PE, PEX, PB and PVDF. -
UNC and UNF - Unified Inch Screw Threads
ANSI/ASME B1.1 Unified National Thread - UNC Coarse series and UNF Fine series. -
US Bolts - Tensile Strength and Proof Loads
Tensile strength and proof loads SAE bolts. -
Wrench Spanners - Inches vs. mm
Convert between US Inches and metric mm wrench and spanner sizes. -
Young's Modulus, Tensile Strength and Yield Strength Values for some Materials
Young's Modulus (or Tensile Modulus alt. Modulus of Elasticity) and Ultimate Tensile Strength and Yield Strength for materials like steel, glass, wood and many more.
