NORD-LOCK® ORGINAL WASHERS

Product information

Find out everything you need to know about our original washers, from material specifications to guidance on choosing the appropriate product for your application.

All types of Nord-Lock washers
Material type
Steel	Stainless steel (ss)	254 SMO®	ALLOY C-276	ALLOY 718
Applications
General steel applications	General stainless steel applications. Non chlorine / acid environments	General salt water applications, pumps, chloride applications, heat exchangers, nuclear, desalination, food processing & medical equipment	General acidic environments, process and chemical industry, evaporators, offshore downhole tooling	Applications with high temperatures, gas turbines, turbo charges, incinerators
Material standard
EN 1.7182	EN 1.4404	EN 1.4547	EN 2.4819 or equivalent	EN 2.4668 or equivalent
Size range
Regular outer diameter M3-M130, #5 to 5" Enlarged outer diameter M3.5-M36, #6 to 1 3/8"	Regular outer diameter M3-M80, #5 to 3 1/8" Enlarged outer diameter M3.5-M30, #6 to 1 1/8"	Regular outer diameter M3-M39, #5 to 1 1/2" Enlarged outer diameter M3.5-M27, #6-1"	Regular outer diameter M4-M20, #8 to 5/8" Enlarged outer diameter M8-M12, 5/16"	Regular outer diameter M4-M20, #8 to 3/4" Enlarged outer diameter M8-M12, 5/16"
Corrosion resistance
Minimum 1,000 hours in salt spray test (according to ISO 9227)	PREN 27**	PREN 45**	PREN 68**	PREN 29**
Hardening
Through hardened	Surface hardened	Surface hardened	Surface hardened	Surface hardened
Washer hardness*
≥ 465HV1	≥ 520HV0,05	≥ 600HV0,05	≥ 520HV0,05	≥ 620HV0,05
Coating
Delta Protekt® KL100 zinc flake coating	-	-	-	-
Bolt grades
Up to 12.9	Up to A4-80
Temperature range***
-50°C to 200°C	-160°C to 500°C	-160°C to 500°C	-160°C to 500°C	-160°C to 700°C
Product designation
NL NLsp	NLss NLspss	NLss-254 NLspss-254	NLss-276 NLspss-276	NLss-718 NLspss-718
Laser Marking - Nord-Lock, traceable batch number and type code:
flZn	SS	254	276	718

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

** PREN (Pitting Resistance Equivalent Number) = %Cr + 3,3x%Mo + 16x%N. Figures in table valid for base material.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

NORD-LOCK STEEL WASHERS
Applications	General steel applications
Material standard	EN 1.7182
Size range	Regular outer diameter M3-M130, #5 to 5" Enlarged outer diameter M3.5-M36, #6 to 1 3/8"
Corrosion resistance	Minimum 1,000 hours in salt spray test (according to ISO 9227)
Hardening	Through hardened
Washer hardness*	≥ 465HV1
Coating	Basecoat Delta Protekt® KL100, Topcoat VH 302 GZ Standard products in range M6-M24 are available with Delta Seal GZ Black top coat
Bolt grades	Up to 12.9
Temperature range***	-50°C to 200°C
Product designation	NL NLsp
Laser Marking - Nord-Lock, traceable batch number and type code:	flZn

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

NORD-LOCK STAINLESS STEEL WASHERS
Applications	General stainless steel applications. Non chlorine / acid environments
Material standard	EN 1.4404
Size range	Regular outer diameter M3-M80, #5 to 3 1/8" Enlarged outer diameter M3.5-M30, #6 to 1 1/8"
Corrosion resistance	PREN 27**
Hardening	Surface hardened
Washer hardness*	≥ 520HV0,05
Bolt grades	Up to A4-80
Temperature range***	-160°C to 500°C
Product designation	NLss NLspss
Laser Marking - Nord-Lock, traceable batch number and type code:	SS

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

** PREN (Pitting Resistance Equivalent Number) = %Cr + 3,3x%Mo + 16x%N. Figures in table valid for base material.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

NORD-LOCK 254 SMO® WASHERS
Applications	General salt water applications, pumps, chloride applications, heat exchangers, nuclear, desalination, food processing & medical equipment
Material standard	EN 1.4547
Size range	Regular outer diameter M3-M39, #5 to 1 1/2" Enlarged outer diameter M3.5-M27, #6-1"
Corrosion resistance	PREN 45**
Hardening	Surface hardened
Washer hardness*	≥ 600HV0,05
Temperature range***	-160°C to 500°C
Product designation	NLss-254 NLspss-254
Laser Marking - Nord-Lock, traceable batch number and type code:	254

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

** PREN (Pitting Resistance Equivalent Number) = %Cr + 3,3x%Mo + 16x%N. Figures in table valid for base material.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

Nord-Lock Alloy C-276 Washers
Applications	General acidic environments, process and chemical industry, evaporators, offshore downhole tooling
Material standard	EN 2.4819 or equivalent
Size range	Regular outer diameter M4-M20, #8 to 5/8" Enlarged outer diameter M8-M12, 5/16"
Corrosion resistance	PREN 68**
Hardening	Surface hardened
Washer hardness*	≥ 520HV0,05
Temperature range***	-160°C to 500°C
Product designation	NLss-276 NLspss-276
Laser Marking - Nord-Lock, traceable batch number and type code:	276

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

** PREN (Pitting Resistance Equivalent Number) = %Cr + 3,3x%Mo + 16x%N. Figures in table valid for base material.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

Nord-Lock Alloy 718 Washers
Applications	Applications with high temperatures, gas turbines, turbo charges, incinerators
Material standard	EN 2.4668 or equivalent
Size range	Regular outer diameter M4-M20, #8 to 3/4" Enlarged outer diameter M8-M12, 5/16"
Corrosion resistance	PREN 29**
Hardening	Surface hardened
Washer hardness*	≥ 620HV0,05
Temperature range***	-160°C to 700°C
Product designation	NLss-718 NLspss-718
Laser Marking - Nord-Lock, traceable batch number and type code:	718

* In order to assure the unique mechanical locking function of the Nord-Lock washers, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers.

** PREN (Pitting Resistance Equivalent Number) = %Cr + 3,3x%Mo + 16x%N. Figures in table valid for base material.

*** Temperature recommendations based on information from the raw material supplier and from tests. Locking function not affected within the specification.

Hardness Conversion Table

Vickers HV	Brinell HB	Rockwell HRC	Rockwell HRA	8.8 bolt	10.9 bolt	12.9 bolt
300	285	29,8	65,5	\|
310	295	31,0	65,8	\|
320	304	32,2	66,4	\|	320 HV
330	314	33,3	67,0	\|	\|
335	319	33,9	67,3	335 HV	\|
340	325	34,4	67,6		\|
350	333	35,5	68,1		\|
360	342	36,6	68,7		\|
370	352	37,7	69,2		\|
380	361	38,8	69,8		380 HV
385	366	39,3	70,1			385 HV
390	371	39,8	70,3			\|
400	380	40,8	70,8			\|
410	390	41,8	71,4			\|
420	399	42,7	71,8			\|
430	409	43,6	72,3			\|
435	414	44,1	72,5			435 HV
440	418	44,5	72,8
460	437	46,1	73,6
480	(456)	47,7	74,5
500	(475)	49,1	75,3
520	(494)	50,5	76,1
540	(513)	51,7	76,7