What is the tensile stress area of a bolt?

The tensile stress area (As) is the effective cross-sectional area used to calculate the tensile load capacity of a threaded fastener. It is smaller than the nominal shank area because it accounts for the thread root geometry. It is defined in ISO 898-1 and depends on the pitch diameter and minor diameter of the thread.

How is bolt tensile strength calculated?

Bolt ultimate tensile load is calculated as Ft = Rm × As, where Rm is the ultimate tensile strength of the bolt material (determined by property class) and As is the tensile stress area. For example, a class 8.8 bolt has Rm = 800 MPa.

What does bolt property class 8.8 mean?

The first number (8) represents 1/100th of the minimum ultimate tensile strength in MPa (800 MPa). The second number (8) represents 10× the ratio of yield strength to ultimate tensile strength (0.8). So yield = 800 × 0.8 = 640 MPa.

How is bolt shear strength calculated?

ISO 898-1 does not specify shear strength — it covers tensile and proof-load properties only. A common simplified estimate takes shear strength as 60% of tensile strength: Fs = 0.6 × Rm × As, based on the von Mises yield criterion. Design codes such as Eurocode 3 (EN 1993-1-8) apply their own factors (0.6 or 0.5 depending on property class) plus partial safety factors. For single shear, use one stress area; for double shear, multiply by 2.

What is the difference between proof load and tensile strength?

Proof load is the maximum force a bolt can withstand without permanent deformation (elastic limit). Ultimate tensile strength is the maximum force before fracture. The proof load stress (Sp) is approximately 90% of the yield strength for most property classes.

ಉಚಿತ ಎಂಜಿನಿಯರಿಂಗ್ ಟೂಲ್

Bolt Tensile & Shear Strength Calculator

Calculate the ultimate tensile load of metric bolts from ISO 898-1 property-class data, plus a simplified shear capacity estimate. Select bolt size and property class.

ISO 898-1 M3 – M64 ವರ್ಗ 4.6 – 12.9

р▓мр│Лр▓▓р│Нр▓Яр│Н р▓Чр▓╛р▓др│Нр▓░

ಗುಣಲಕ್ಷಣ ವರ್ಗ

ಶಿಯರ್ ಸಮತಲಗಳು

Quick presets

Results

ಅಂತಿಮ ತಾಣ ಲೋಡ್ (Ft)

—

Shear Capacity (Fs, simplified estimate)

—

ತಾಣ ಒತ್ತಡ ಪ್ರದೇಶ (As)

—

ಯೀಲ್ಡ್ ಲೋಡ್ (Fy)

—

ಅಂತಿಮ ತಾಣ ಬಲ (Rm)

—

ಅಂತಿಮ ತಾಣ ಲೋಡ್

ಭಂಗಕ್ಕೂ ಮೊದಲು ಬೋಲ್ಟ್ ತಾಳಬಲ್ಲ ಗರಿಷ್ಠ ತಾಣ ಬಲ:

R_m — ಅಂತಿಮ ತಾಣ ಬಲ (MPa), ಗುಣಲಕ್ಷಣ ವರ್ಗದಿಂದ
A_s — ತಾಣ ಒತ್ತಡ ಪ್ರದೇಶ (mm²), ISO 898-1 / ISO 261 ಪ್ರಕಾರ

Shear Capacity (Simplified Estimate)

ISO 898-1 defines the tensile and proof-load properties of bolts — it does not specify shear strength. The value shown here is a widely used simplified engineering estimate that takes shear strength as approximately 60% of tensile strength (based on the von Mises criterion, τ ≈ 0.58 σ):

ದ್ವಿ ಶಿಯರ್‌ಗಾಗಿ 2ರಿಂದ ಗುಣಿಸಿ (ಎರಡು ಶಿಯರ್ ಸಮತಲಗಳು).

⚠️ Shear design note: Actual shear capacity depends on whether the shear plane passes through the threads or the unthreaded shank, on joint slip and plate bearing, and on fatigue loading. Design codes define their own values — e.g. Eurocode 3 (EN 1993-1-8) uses F_v = α_v × f_ub × A with α_v = 0.6 for classes 4.6, 5.6 and 8.8 but 0.5 for classes 4.8, 5.8, 6.8 and 10.9, together with partial safety factors. Always verify shear-loaded joints against the applicable structural or mechanical design code, not this simplified estimate alone.

ISO 898-1 ಪ್ರಕಾರದ ಗುಣಲಕ್ಷಣ ವರ್ಗಗಳು

ವರ್ಗ	Rm (MPa)	Rp0.2 (MPa)	ಸಾಮಾನ್ಯ ಬಳಕೆ
4.6	400	240	ಕಡಿಮೆ ಬಲ, ಸಾಮಾನ್ಯ ಉದ್ದೇಶ
5.8	520	420	ರಚನಾತ್ಮಕ, ಪೂರ್ವಭಾರವಿಲ್ಲದ
8.8	800	640	ವಾಹನೋದ್ಯಮ, ಯಂತ್ರೋಪಕರಣಗಳು (ಅತ್ಯಂತ ಸಾಮಾನ್ಯ)
10.9	1040	940	ಹೆಚ್ಚು-ಬಲದ ರಚನಾತ್ಮಕ
12.9	1220	1100	ಗರಿಷ್ಠ ಬಲ (ಅಲೊಯ್ ಉಕ್ಕು)

ಪ್ರಾಯೋಗಿಕ ಉದಾಹರಣೆ

ಉದಾಹರಣೆ — M10 × 8.8 ಬೋಲ್ಟ್

Given: M10 ಬೋಲ್ಟ್, ಗುಣಲಕ್ಷಣ ವರ್ಗ 8.8, ಏಕ ಶಿಯರ್

A_s = 58.0 mm², R_m = 800 MPa

F_ಟಿ = 800 × 58.0 = 46,400 N = 46.4 kN

F_s = 0.6 × 800 × 58.0 = 27,840 N = 27.8 kN

⚠️ Note: ಇವು ಸುರಕ್ಷತಾ ಗುಣಾಂಕಗಳಿಲ್ಲದ ಅಂತಿಮ ಸಾಮರ್ಥ್ಯಗಳಾಗಿವೆ. ವಿನ್ಯಾಸ ಉದ್ದೇಶಗಳಿಗೆ ಸೂಕ್ತ ಸುರಕ್ಷತಾ ಗುಣಾಂಕಗಳನ್ನು ಅನ್ವಯಿಸಿ (ಸಾಮಾನ್ಯವಾಗಿ ಸ್ಥಿರ ಭಾರಕ್ಕೆ 2–3, ದಣಿವಿಗೆ 4–6).