Hansen HK Series Steel Couplings

Danfoss Hansen HK Series steel quick disconnect couplings are designed for high-pressure hydraulic applications requiring strength, durability, and reliable performance.

Hansen HK Series Steel

Hansen HK Series steel couplings are heavy-duty hydraulic quick disconnect couplings built for demanding fluid transfer systems. Commonly used in construction equipment, agricultural machinery, and industrial hydraulic systems, they are designed for high pressure service and rugged performance.

With a design history dating back to 1915, the Hansen HK series reflects the original quick-release coupling concept developed by Fred Hansen. Built to ISO 7241-1 Series B standards, HK Series couplings provide reliable interchangeability, secure connections, and long service life in harsh operating environments.

Key Features

ISO 7241-1 Series B interchange compatibility
Heavy-duty ball latch design for secure connection
Self-sealing poppet valves to minimize fluid loss
Standard seal: Buna-N (Nitrile)
Optional seals: FKM, EPDM, Neoprene, PTFE
Zinc plated steel body with hardened internal components

Flow Data

Common Applications

Industrial Equipment

Agriculture
Hydraulic Tool
General Industry
Construction
Fluid Transfer
Transportation

Critical Service

Military
Law Enforcement/Rescue
Chemical
Oil and Gas
Consumer Products

Commercial & Specialty

HVAC
Food and Beverage
Trucks
Aerospace
Medical

Physical Characteristics

Series	Body Size (in)	ISO Size (mm)	Nominal Flow Diameter (mm)	Non-Hazardous Pressure (bar)	Non-Hazardous Pressure (psi)	Hazardous Pressure (bar)	Hazardous Pressure (psi)	Rated Flow (lpm)	Rated Flow (gpm)	Air Inclusion cc max.	Fluid Loss cc max.
1HK	1/8	5	4.4	275	4,000	275	4,000	3	0.8	0.6	0.5
2HK	1/4	6.3	5.9	345	5,000	345	5,000	12	3	1.2	0.9
3HK	3/8	10	7.8	275	4,000	275	4,000	23	6	2.9	2.1
4HK	1/2	12.5	10	345	5,000	345	5,000	45	12	3.6	3.5
6HK	3/4	20	17	275	4,000	275	4,000	100	26	11.5	9.3
8HK	1	25	19.6	275	4,000	275	4,000	189	50	18.0	16.9
10HK	1 1/4	—	26.7	200	2,900	37	537	288	76	48.0	48.0
12HK	1 1/2	40	35.1	150	2,175	29	421	375	99	91.3	91.3
20HK	2 1/2	50	46	100	1,450	21	305	757	200	209.9	209.9

For questions related to vacuum please contact Danfoss.

No ISO Standard available for the 10HK.

HK Series Steel Part Numbers

Below are common Hansen HK Series steel coupling configurations. Contact us for additional sizes and options.

Sockets (Female)

Use the diagram as a quick reference for dimensions:

A = Overall Length
B = Body Length
HEX = Wrench Size

Part Number	Body Size (in)	ISO Size (mm)	Thread Size	Fig.	A (in)	B (in)	Hex (in)
1H11	1/8	5	1/8-27 NPTF	1	1.91	0.98	0.56
1H4	1/8	5	1/4-20 SAE	1	2.06	0.98	0.69
2H16	1/4	6.3	1/4-18 NPTF	1	2.26	1.14	0.75
2H16BS	1/4	6.3	1/4-19 BSPP	1	2.31	1.14	0.75
2H6	1/4	6.3	9/16-18 SAE	1	2.40	1.14	0.88
3H21	3/8	10	3/8-18 NPTF	1	2.56	1.42	0.88
3H21BS	3/8	10	3/8-19 BSPP	1	2.56	1.42	0.88
3H8	3/8	10	3/4-16 SAE	1	2.74	1.42	1.00
4HP26	1/2	12.5	1/2-14 NPTF	1	2.96	1.86	1.13
4HP26BS	1/2	12.5	1/2-14 BSPP	1	2.96	1.86	1.13
4HP10	1/2	12.5	7/8-14 SAE	1	3.05	1.86	1.25
6HP31	3/4	20	3/4-14 NPTF	1	3.48	2.22	1.31
6HP31BS	3/4	20	3/4-14 BSPP	1	3.48	2.22	1.31
6HP12	3/4	20	1-1/16-12 SAE	1	3.67	2.22	1.38
8HP36	1	25	1-11 1/2 NPTF	1	4.13	2.61	1.75
8HP36BS	1	25	1-11 BSPP	1	4.13	2.61	1.75
8HP16	1	25	1-1/8-12 SAE	1	4.13	2.61	1.88

Plugs (Male)

Use the diagram as a quick reference for plug dimensions:

C = Overall Length
D = Body Length
E / HEX = Nose / Wrench Size

Part Number	Body Size (in)	ISO Size (mm)	Thread Size	Fig.	C (in)	D (in)	E (in)	Hex (in)
1K11	1/8	5	1/8-27 NPTF	3	1.26	0.65	0.44	0.56
1K4	1/8	5	7/16-20 SAE	3	1.41	0.79	0.59	0.69
2K16	1/4	6.3	1/4-18 NPTF	3	1.52	0.87	0.56	0.75
2K16BS	1/4	6.3	1/4-19 BSPP	3	1.52	0.87	0.56	0.75
2K6	1/4	6.3	9/16-18 SAE	3	1.66	1.01	0.70	0.88
3K21	3/8	10	3/8-18 NPTF	3	1.76	1.01	0.61	0.88
3K21BS	3/8	10	3/8-19 BSPP	3	1.76	1.01	0.61	0.88
3K8	3/8	10	3/4-16 SAE	3	1.94	1.15	0.79	1.00
4KP26	1/2	12.5	1/2-14 NPTF	3	2.03	1.30	0.76	1.13
4KP26BS	1/2	12.5	1/2-14 BSPP	3	2.03	1.30	0.76	1.13
4KP10	1/2	12.5	7/8-14 SAE	3	2.11	1.37	0.84	1.19
6KP31	3/4	20	3/4-14 NPTF	3	2.36	1.52	0.71	1.31
6KP31BS	3/4	20	3/4-14 BSPP	3	2.36	1.52	0.71	1.31
6KP12	3/4	20	1-1/16-12 SAE	3	2.54	1.59	0.89	1.38
8KP36	1	25	1-11 1/2 NPTF	3	2.85	1.88	0.97	1.63
8KP36BS	1	25	1-11 BSPP	3	2.85	1.88	0.97	1.63
8KP16	1	25	1-5/16-12 SAE	3	2.85	2.17	0.97	1.88

Large Sockets (10HK-20HK)

Use this section for larger HK Series socket part numbers from 10HK through 20HK.

Use the diagram as a reference for larger coupling dimensions:

A = Overall Length
B = Body Length
HEX = Wrench Size

Part Number	Body Size (in)	ISO Size (mm)	Thread Size	Fig.	A (in)	B (in)	Hex (in)
10H41	1 1/4	–	1 1/4-11 1/2 NPTF	2	4.51	2.73	2.38
10H41BS	1 1/4	–	1 1/4-11 BSPP	2	4.51	2.73	2.38
12H41	1 1/2	40	1 1/4-11 1/2 NPTF	2	4.82	3.23	2.38
12H46	1 1/2	40	1 1/2-11 1/2 NPTF	2	4.82	3.23	2.38
20H51	2 1/2	50	2-11 1/2 NPTF	2	5.55	4.11	3.75
20H56	2 1/2	50	2 1/2-8 NPTF	2	6.14	4.11	3.75
20H61	2 1/2	50	3-8 NPTF	2	7.00	4.11	4.00

* ISO 7241-1 Series B does not include 1-1/4 inch body size couplings; therefore, Series 10HK is not covered by this standard.

Large Plugs (10HK-20HK)

Use this section for larger HK Series plug part numbers from 10HK through 20HK.

Use the diagram as a reference for larger plug dimensions:

C = Overall Length
D = Body Length
E / HEX = Nose / Wrench Size

Part Number	Body Size (in)	ISO Size (mm)	Thread Size	Fig.	C (in)	D (in)	E (in)	Hex (in)
10K41	1 1/4	–	1 1/4-11 1/2 NPTF	4	4.25	2.74	2.33	2.38
10K41BS	1 1/4	–	1 1/4-11 BSPP	4	4.25	2.74	2.33	2.38
12K41	1 1/2	40	1 1/4-11 1/2 NPTF	4	4.76	2.74	2.67	2.38
12K46	1 1/2	40	1 1/2-11 1/2 NPTF	4	4.76	2.74	2.67	2.38
12K46BS	1 1/2	40	1 1/2-11 BSPP	4	4.76	2.74	2.67	2.38
20K51	2 1/2	60	2-11 1/2 NPTF	4	5.49	4.33	2.97	3.75
20K56	2 1/2	60	2 1/2-8 NPTF	4	6.08	4.33	3.56	3.75
20K61	2 1/2	60	3-8 NPTF	4	6.94	4.62	4.42	4.00

* ISO 7241-1 Series B does not include 1-1/4 inch body size couplings; therefore, Series 10HK is not covered by this standard.

Dust Plugs and Dust Caps Accessories

Protect HK couplings when disconnected with matching metal or vinyl accessories.

Use the diagram as a quick reference for HK dust cap and dust plug accessories.

Match the accessory series to the coupling series.
Metal and vinyl options are shown in the table below.
Contact us if you need help matching an accessory to an existing coupling.

Hansen HK Dust Caps and Dust Plugs Diagram

Coupling Series	Plug Dust Cap Metal	Plug Dust Cap Vinyl	Socket Dust Plug Metal	Socket Dust Plug Vinyl
1HK	XPDC1HK*	XPPDC1HK	SDC1HK**	XPSDC1HK
2HK	XPDC2HK**	XPPDC2HK	SDC2HK**	XPSDC2HK
3HK	XPDC3HK*	XPPDC3HK	SDC3HK**	XPSDC3HK
4HK	XPDC4HK**	XPPDC4HK(RD)***	SDC4HK**	XPSDC4HK(RD)***
6HK	XPDC6HK**	XPPDC6HK(RD)***	SDC6HK**	XPSDC6HK(RD)***
8HK	XPDC8HK**	XPPDC8HK(RD)***	SDC8HK**	XPSDC8HK(RD)***
12HK	XPDC12HK*		SDC12HK*
20HK	XPDC20HK**		SDC20HK**

* Brass

** Aluminum

*** Offered in red by adding RD to end of part number