How do I convert MPa to ksi?

1 ksi = 6.89476 MPa. To convert MPa to ksi: divide by 6.89476. Example: 500 MPa = 72.5 ksi.

What is the difference between MPa and N/mm²?

They are identical. 1 MPa = 1 N/mm² = 1 MN/m². Both are commonly used in engineering for stress and strength values.

How do I convert stress to force?

Force = Stress × Area (F = σ × A). For example, 500 MPa stress on a 100 mm² cross-section: F = 500 × 100 = 50,000 N = 50 kN.

What is kgf/mm² and when is it used?

Kilogram-force per square millimeter. An older metric unit still used in some Russian, Japanese, and older European standards. 1 kgf/mm² = 9.80665 MPa.

What are typical steel strength values?

S235: Rp=235 MPa, Rm=360 MPa. S355: Rp=355 MPa, Rm=510 MPa. AISI 4140 Q&T: Rp=655 MPa, Rm=900 MPa. Stainless 304: Rp=210 MPa, Rm=520 MPa.

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強度單位轉換器

立即在 9 種應力/強度單位之間轉換。在任何單位中輸入數值 — 同時查看所有轉換結果。包含應力至力計算器與材料參考資料。

MPa ksi PSI GPa kgf/mm² bar kPa

數值

來源單位

截面積 (mm²) — 用於 σ→F

常見材料強度

所有單位

MPa (= N/mm²)

—

ksi (kip/in²)

—

PSI (lbf/in²)

—

GPa

—

kPa

—

bar

—

kgf/mm²

—

kgf/cm²

—

應力 → 力 (F = σ × A)

力

—

力 (kN)

—

力 (公噸力)

—

轉換關係

應力轉力

實務範例

範例 — 轉換 S355 降伏應力

已知： Rp0.2 = 355 MPa

= 355 N/mm² = 0.355 GPa = 355,000 kPa

= 355 / 6.895 = 51.5 ksi = 51,488 PSI

= 355 / 9.807 = 36.2 kgf/mm²

= 355 × 10 = 3,550 bar

200 mm² 棒材上的力：F = 355 × 200 = 71,000 N = 71.0 kN

材料強度參考表

材料	標準	Rp0.2 (MPa)	Rm (MPa)	Rp (ksi)	Rm (ksi)
S235JR	EN 10025	235	360–510	34.1	52–74
S275JR	EN 10025	275	410–560	39.9	59–81
S355JR	EN 10025	355	470–630	51.5	68–91
P265GH	EN 10028	265	410–530	38.4	59–77
P355GH	EN 10028	355	490–630	51.5	71–91
A36	ASTM	250	400–550	36	58–80
A516 Gr.70	ASTM	260	485–620	37.7	70–90
304 不鏽鋼	EN/ASTM	210	520–720	30.5	75–104
316L 不鏽鋼	EN/ASTM	200	500–700	29.0	73–101
42CrMo4 Q&T	EN 10083	750	1000–1200	109	145–174
AISI 4140 Q&T	ASTM	655	900–1100	95	131–160
Duplex 2205	EN/ASTM	450	620–880	65.3	90–128

💡 提示： 1 MPa = 1 N/mm² 精確相等。這是國際標準中機械性能最常用的單位。在美國，標準單位為 ksi（= 1000 PSI）。