Clufix : Recommended Torque

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Recommended Torque

Threaded elements / Recommended torque

When an assembly is made, a torque (Cs) is applied to the screw or bolt and nut system, so that the force (Fo) generates a clamping force on the entire assembly. For a given torque (Cs) applied, the Fo value is dependent on the system’s friction coefficient (μ).

The table here after (extract from the NF E 25-030 standard: Screw or bolt elements – Screwed assemblies – Design, calculation and assembly conditions) shows maximum recommended torque (in accordance with the assembled screw or bolt and nut elements).

		Screw or bolt Ø	3	4	5	6	8	10	12	14	16
		Pitch	0.5	0.7	0.8	1	1.25	1.5	1.75	2	2
Grade	μ	Dimension across-flats	5.5	7	8	10	13	16	18	21	21
6.8 Rm = 600 N/mm² Re = 480 N/mm²	0.10	Cs (Nm)	0.71	1.65	3.25	5.6	13.6	27	46	75	115
	0.10	Fo (N)	1724	2988	4885	6896	12647	20128	29339	40280	55356
	0.15	Cs (Nm)	0.91	2.09	4.14	7.1	17.4	34	59	95	148
	0.15	Fo (N)	1556	2696	4414	6226	11432	18206	26550	36463	50216
	0.20	Cs (Nm)	1.06	2.42	4.81	8.3	20	40	69	111	174
	0.20	Fo (N)	1399	2422	3970	5598	10283	16382	23895	32822	45248
8.8 Rm = 800 N/mm² Re = 640 N/mm²	0.10	Cs (Nm)	0.95	2.20	4.34	7.5	18.2	36	62	99	153
	0.10	Fo (N)	2298	3985	6514	9195	16863	26838	39119	53707	73808
	0.15	Cs (Nm)	1.21	2.78	5.5	9.5	23	46	79	127	198
	0.15	Fo (N)	2075	3594	5836	8302	15242	24275	35401	48618	66955
	0.20	Cs (Nm)	1.41	3.22	6.4	11.1	27	53	92	148	232
	0.20	Fo (N)	1866	3230	5293	7464	13710	21843	31860	43763	60331
10.9 Rm = 1000 N/mm² Re = 900 N/mm²	0.10	Cs (Nm)	1.40	3.23	6.3	11	26	52	91	145	225
	0.10	Fo (N)	3376	5853	9568	13506	24768	39418	57457	78882	108406
	0.15	Cs (Nm)	1.79	4.09	8.1	14	34	67	116	187	291
	0.15	Fo (N)	3048	5279	8645	12194	22388	35655	51995	71408	98340
	0.20	Cs (Nm)	2.07	4.74	9.4	16.3	39	78	136	218	341
	0.20	Fo (N)	2740	4744	7774	10962	20137	32082	46795	64277	88611
12.9 Rm = 1200 N/mm² Re = 1080 N/mm²	0.10	Cs (Nm)	1.64	3.78	7.4	12.6	31	61	106	170	263
	0.10	Fo (N)	3951	6849	11196	15805	28984	46128	67236	92309	126858
	0.15	Cs (Nm)	2.09	4.79	9.5	16.4	40	79	136	219	341
	0.15	Fo (N)	3567	6178	10116	14269	26198	41724	60845	83563	115079
	0.20	Cs (Nm)	2.43	5.5	11	19.1	46	92	159	255	399
	0.20	Fo (N)	3207	5552	9098	12828	23565	37542	54760	75218	103964

Rm = tensile strength
Re = elastic strength

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