Duplex Hex Head Bolts

Duplex 2205 and Super Duplex 2507 hex head bolts are supplied for high-chloride, marine, offshore and corrosion-critical structures where standard 304 / 316 stainless may not provide enough pitting and crevice corrosion resistance. Standards include DIN 931, DIN 933, ISO 4014, ISO 4017 and ASTM F593 project references.

Duplex 2205 corresponds commonly to UNS S32205 / S31803, while Super Duplex 2507 corresponds to UNS S32750. These alloys provide higher strength than common austenitic stainless grades and improved chloride resistance, but material selection should consider temperature, environment, galvanic compatibility and project corrosion class.

Common supply range is M12-M36, with partial-thread or full-thread hex head geometry by drawing. Pickled and passivated finishes help restore stainless corrosion resistance after forming, machining or heat exposure, and PMI / MTC documentation is often required for offshore and oil and gas procurement.

Dimensions & SpecificationsDIN 931 / ISO 4014

Technical Drawing

Dimensional Table

Grade AGrade B

Parameter	M1.6	M2	M2.5	M3	M3.5	M4	M5	M6	M7	M8	M10	M12	M14	M16	M18	M20	M22	M24
P	0.35	0.4	0.45	0.5	0.6	0.7	0.8	1	1	1.25	1.5	1.75	2	2	2.5	2.5	2.5	3
da/max	2	2.6	3.1	3.6	4.1	4.7	5.7	6.8	7.8	9.2	11.2	13.7	15.7	17.7	20.2	22.4	24.4	26.4
ds/max	1.6	2	2.5	3	3.5	4	5	6	7	8	10	12	14	16	18	20	22	24
ds/min	1.46	1.86	2.36	2.86	3.32	3.82	4.82	5.82	6.78	7.78	9.78	11.73	13.73	15.73	17.73	19.67	21.67	23.67
e/min	3.41	4.32	5.45	6.01	6.58	7.66	8.79	11.05	12.12	14.38	18.9	21.1	24.49	26.75	30.14	33.53	35.72	39.98
k/max	1.22	1.52	1.82	2.12	2.52	2.92	3.65	4.15	4.95	5.45	6.58	7.68	8.98	10.18	11.72	12.72	14.22	15.22
k/min	0.98	1.28	1.58	1.88	2.28	2.68	3.35	3.85	4.65	5.15	6.22	7.32	8.62	9.82	11.28	12.28	13.78	14.78
r/min	0.1	0.1	0.1	0.1	0.1	0.2	0.2	0.25	0.25	0.4	0.4	0.6	0.6	0.6	0.6	0.8	0.8	0.8
s/max	3.2	4	5	5.5	6	7	8	10	11	13	17	19	22	24	27	30	32	36
s/min	3.02	3.82	4.82	5.32	5.82	6.78	7.78	9.78	10.73	12.73	16.73	18.67	21.67	23.67	26.67	29.67	31.61	35.38