HEICO-TEC® Tension Nuts

Name: HEICO-TEC® Tension Nuts
Brand: HEICO

Multi-jackbolt tension nuts: preload large bolts M20 to M160 precisely with a hand torque wrench. Class 8 and 10 to ISO 898-2.

★ Hero product HEICO-TEC® Tension Nuts

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Overview

Large bolts need huge torque. Hydraulic tensioners and torque multipliers are heavy, slow to set up and, with hydraulic tensioning, part of the bolt stretch is lost when the pressure is released, so only about two thirds of the bolt strength is used.

A HEICO-TEC® Tension Nut divides the job. The nut body is screwed onto the main thread but not tightened. A ring of small pressure bolts around the thread pushes pressure pins onto a hardened thrust washer. Tightening the pressure bolts one after another with a normal torque wrench stretches the main bolt to full preload.

The preload is purely axial, with no torsion or bending in the main bolt, so the bolt strength can be fully used. There are no settlement losses, the pressure pins act like springs that keep the joint elastic, and controlled friction gives high, repeatable accuracy confirmed by DNV GL. The nuts are not damaged and can be re-used.

Class 8 and class 10 nuts meet ISO 898-2, passed load tests at an official materials testing institute (MPA) witnessed by DNV GL and TÜV Süd, and can replace hex nuts of the same class 1:1. Class 8 nuts are TÜV approved for pressure equipment.

Specifications

Brand	HEICO-TEC® (HEICO Befestigungstechnik GmbH, Ense, Germany)
Class 8 (ISO 898-2)	M20 to M160
Class 10 (ISO 898-2)	M20 to M100
Inch (ASTM A563 B, C, D)	1″ to 6″
Tightening	Hand torque wrench on the pressure bolts
Preload	Purely axial, no torsion; up to 2/3 (cl. 8) or 3/4 (cl. 10) of bolt breaking load
Temperature	−20 to 300 °C (class 10: −40 °C; −60 °C on request)
Approvals / tests	MPA load tests witnessed by DNV GL and TÜV Süd; TÜV for pressure equipment (class 8)
Coating	Optional zinc flake; stainless and other coatings on request
Range	Compact Series, Reaction Nuts, Tension Bolts, Light Series, Multi-Tool, protection caps, accessories
Supplied by	Kantilal & Brothers, authorised HEICO distributor

How it works

HEICO-TEC tension nut working principle — 1 Nut body · 2a pressure bolts · 2b pressure pins · 3 hardened thrust washer. Tightening the small pressure bolts stretches the main bolt axially.

Images © HEICO Befestigungstechnik GmbH, used by Kantilal & Brothers as authorised HEICO distributor.

The HEICO-TEC® range

Type	Standard / grade	Use	Sizes	Temperature
HTM/8 Tension Nut	ISO 898-2 class 8	Replaces hex nut class 8; TÜV approved for pressure equipment (2014/68/EU, AD 2000)	M20–M160	−20 to 300 °C (−60 °C on request)
HTM/10 Tension Nut	ISO 898-2 class 10	Replaces hex nut class 10	M20–M100	−40 to 300 °C
HTM/BH, CH, DH	ASTM A563 grade B, C, D	Inch replacement for hex and heavy hex nuts	1″–6″	−20 / −40 to 300 °C
HTM/LT Light Series	Large diameter	Press columns, foundations, tie rods	M90–M250	−20 to 300 °C
HTM/FL, HTM/FS Compact Series	Flat light / heavy	Tight spaces, rotating parts, hydraulic cylinders; set screws inside the body	M20–M160, 1″–6″	−20 to 300 °C
HTR/8, HTR/10 Reaction Nut	ISO 898-2 class 8 / 10	Passive (reaction) end of through-bolts; elastic, adds joint length	M20–M160 / M20–M100	−20 / −40 to 300 °C
HTS/8.8, HTZ/8.8 Tension Bolt	ISO 898-1 class 8.8	Replaces hex bolt ISO 4014 / socket cap ISO 4762 in confined spaces	M20–M160	−20 to 300 °C
Multi-Tool, protection caps, accessories	—	Torque tools, anti-rotation discs, caps for pressure bolts	—	—

Sizes and technical data

Property class 8 (ISO 898-2) · M20–M160 · 32 sizes

Item	Thread	Nut Ø D_o (mm)	Height h (mm)	Pressure bolts n	Width across flats (mm)	Washer Ø (mm)	Washer w (mm)	Total height H (mm)	Stroke a (mm)	Torque per pressure bolt (Nm)	Nominal preload (kN)	Max. bolt load (kN)
HTM-M20x2.5/8	M20×2.5	40	20	7	6	39	4	37	4.5	12	125	160
HTM-M22x2.5/8	M22×2.5	42	20	8	6	41	4	37	4.5	14	165	190
HTM-M24x3/8	M24×3	44	20	10	6	43	4	37	4.5	13	195	225
HTM-M27x3/8	M27×3	50	24	8	7	49	4	42	5.0	24	245	285
HTM-M30x3.5/8	M30×3.5	56	28	9	8	55	5	50	5.5	30	300	360
HTM-M33x3.5/8	M33×3.5	59	28	10	8	58	5	50	5.5	33	365	445
HTM-M36x4/8	M36×4	69	35	7	10	68	5	60	7.5	70	440	525
HTM-M39x4/8	M39×4	72	35	8	10	71	5	60	7.5	73	525	625
HTM-M42x4.5/8	M42×4.5	75	35	9	10	74	5	60	7.5	74	600	720
HTM-M45x4.5/8	M45×4.5	84	42	8	12	83	6	73	9.5	115	685	840
HTM-M48x5/8	M48×5	87	42	9	12	86	6	73	9.5	120	805	945
HTM-M52x5/8	M52×5	91	42	10	12	90	6	73	9.5	125	930	1125
HTM-M56x5.5/8	M56×5.5	102	52	8	14	101	8	87	10.5	205	1095	1300
HTM-M60x5.5/8	M60×5.5	106	52	9	14	105	8	87	10.5	210	1260	1500
HTM-M64x6/8	M64×6	110	52	10	14	109	8	87	10.5	215	1435	1665
HTM-M68x6/8	M68×6	120	64	9	16	119	8	104	12.5	315	1645	1930
HTM-M72x6/8	M72×6	124	64	10	16	123	8	104	12.5	320	1855	2145
HTM-M76x6/8	M76×6	128	64	12	16	127	8	104	12.5	300	2090	2490
HTM-M80x6/8	M80×6	132	76	13	16	131	8	116	12.5	310	2340	2780
HTM-M85x6/8	M85×6	137	76	15	16	136	8	116	12.5	305	2655	3170
HTM-M90x6/8	M90×6	149	88	13	18	148	10	130	12.5	445	3005	3580
HTM-M95x6/8	M95×6	154	88	15	18	153	10	130	12.5	430	3350	4020
HTM-M100x6/8	M100×6	159	88	16	18	158	10	130	12.5	450	3740	4480
HTM-M105x6/8	M105×6	170	100	14	20	169	10	147	14.5	635	4165	4965
HTM-M110x6/8	M110×6	175	100	15	20	174	10	147	14.5	650	4570	5400
HTM-M115x6/8	M115×6	186	112	17	20	185	10	159	14.5	630	5020	6015
HTM-M120x6/8	M120×6	195	112	18	20	194	10	159	14.5	655	5525	6490
HTM-M125x6/8	M125×6	203	124	14	21	202	12	176	18.5	910	6000	7125
HTM-M130x6/8	M130×6	208	124	16	21	207	12	176	18.5	860	6510	7775
HTM-M140x6/8	M140×6	215	124	18	21	214	12	176	18.5	895	7600	9075
HTM-M150x6/8	M150×6	236	139	20	21	235	12	191	18.5	930	8775	10190
HTM-M160x6/8	M160×6	272	139	23	21	271	12	191	18.5	925	10030	11735

Property class 10 (ISO 898-2) · M20–M100 · 23 sizes

Item	Thread	Pitch P1 / P2 / P3	Nut Ø D_o (mm)	Height h (mm)	Pressure bolts n	Width across flats (mm)	Washer Ø (mm)	Washer w (mm)	Total height H (mm)	Stroke a (mm)	Torque per pressure bolt (Nm)	Nominal preload (kN)	Max. bolt load (kN)
HTM-M20x.../10	M20	2.5 / 2 / 1.5	40	20	10	6	39	4	37	4.5	12	180	220
HTM-M22x.../10	M22	2.5 / 2 / 1.5	42	20	12	6	41	4	37	4.5	13	235	265
HTM-M24x.../10	M24	3.0 / 2 / 1.5	46	24	9	7	45	4	42	5.0	22	260	320
HTM-M27x.../10	M27	3.0 / 2 / 1.5	50	24	12	7	49	4	42	5.0	22	350	410
HTM-M30x.../10	M30	3.5 / 2 / 1.5	56	28	12	8	55	5	50	5.5	31	425	505
HTM-M33x.../10	M33	3.5 / 2 / 1.5	66	33	8	10	65	5	56	5.5	70	515	625
HTM-M36x.../10	M36	4.0 / 3 / 1.5	69	35	10	10	68	5	60	7.5	67	620	740
HTM-M39x.../10	M39	4.0 / 3 / 1.5	72	35	12	10	71	5	60	7.5	66	725	880
HTM-M42x.../10	M42	4.5 / 3 / 1.5	81	40	10	12	80	6	69	7.5	110	845	1010
HTM-M45x.../10	M45	4.5 / 3 / 1.5	84	42	11	12	83	6	73	9.5	115	975	1180
HTM-M48x.../10	M48	5.0 / 3 / 1.5	88	42	12	12	87	6	73	9.5	120	1110	1330
HTM-M52x.../10	M52	5.0 / 3 / 2.0	98	50	11	14	97	8	84	9.5	180	1320	1585
HTM-M56x.../10	M56	5.5 / 4 / 2.0	102	52	12	14	101	8	87	10.5	190	1520	1830
HTM-M60x.../10	M60	5.5 / 4 / 2.0	110	52	13	14	109	8	87	10.5	205	1780	2130
HTM-M64x.../10	M64	6.0 / 4 / 2.0	116	60	12	16	115	8	100	12.5	290	2020	2420
HTM-M68x.../10	M68	6.0 / 4 / 2.0	120	64	13	16	119	8	104	12.5	305	2300	2750
HTM-M72x.../10	M72	6.0 / 4 / 2.0	134	64	12	18	133	10	106	12.5	415	2585	3120
HTM-M76x.../10	M76	6.0 / 4 / 2.0	138	72	13	18	137	10	115	13.5	435	2935	3510
HTM-M80x.../10	M80	6.0 / 4 / 2.0	147	72	14	18	146	10	115	13.5	450	3270	3910
HTM-M85x.../10	M85	6.0 / 4 / 2.0	150	84	13	20	149	10	131	14.0	505	3700	4460
HTM-M90x.../10	M90	6.0 / 4 / 2.0	160	84	14	20	159	10	131	14.0	530	4185	5040
HTM-M95x.../10	M95	6.0 / 4 / 2.0	173	94	11	21	172	12	146	18.5	910	4700	5560
HTM-M100x.../10	M100	6.0 / 4 / 2.0	182	94	12	21	181	12	146	18.5	930	5245	6110

Torque is per pressure bolt; torque and preload are proportional (half the torque gives half the preload). Nominal preload: class 8 ≈ 2/3 of the breaking load of an 8.8 bolt; class 10 ≈ 3/4 of the breaking load of a 10.9 bolt. Max. bolt load = preload + working load and must not be exceeded. Optional zinc flake coating; other coatings and stainless on request.

Assembly and disassembly

1 · PrepareClean the bolt thread and contact face and remove burrs. Centre the hardened washer, screw the nut on hand-tight, then back it off about ¼ turn.

2 · SeatSet the torque wrench. Hand-tighten three pressure bolts spaced evenly around the nut until they touch the washer, then take them to torque in steps of max. ½ turn.

3 · TightenTighten three more evenly spaced bolts to torque, then go round all pressure bolts in a circle. Repeat until the wrench turns less than 10° before it clicks.

4 · DisassembleCrack each pressure bolt loose in a circle, then loosen each by max. ¼ turn per round, two or three rounds, until all are unloaded. Unscrew the nut and remove the washer.

Soft materials such as aluminium: use a larger, thicker load-spreading washer (available on request).
Large holes or slots: the washer must be fully supported under the pressure pins; use an extra support washer.
Long protruding bolt ends: an additional washer can be supplied to position the nut.
For strong vibration, secure with the HEICO anti-rotation disc (with HEICO-LOCK® washers), safety wire through cross-drilled pressure bolts, or a radial locking pin.

Key features

No hydraulic or power tools
Purely axial preload, full bolt strength
No settlement losses
High, repeatable accuracy
Replaces hex nuts 1:1
Re-usable
Saves set-up and transport time

Applications

Steel industry and rolling millsPresses, crushers and heavy machineryPower generation and windPressure vessels and flangesMining and cementMarine and offshore

Need a size, grade or finish not listed? We also make special and non-standard parts to drawing. Ask us →