Nord-Lock Original Washers

Nord-Lock created the original wedge-locking technology that secures bolted joints, even when exposed to severe vibration and dynamic loads. It is impossible for our products to loosen unintentionally due to the wedge created underneath the bolt head and nut.

Selection Guide

Application parameter
Steel Stainless steel (ss) 254 SMO® INCONEL®/ HASTELLOY® C-276 INCONEL® 718
Steel type
EN 1.7182 or equivalent EN 1.4404 or equivalent EN 1.4547 or equivalent EN 2.4819 or equivalent EN 2.4667 or equivalent
Examples of 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
Available for bolt sizes

M3-M130

#5 to 5"

M3-M80

#5 to 3 1/8"

M3-M39

#5 to 1 1/2"

M3-M39 available on request

#5 to 1 1/2" available on request

M3-M39 available on request

#5 to 1 1/2" available on request

Washer types

Regular outer diameter (NL3 - NL130)

Enlarged outer diameter (NL3,5sp - NL36sp)

Regular outer diameter (NL3ss-NL80ss)

Enlarged outer diameter (NL3,5spss - NL30spss)

Regular outer diameter (NL3ss-254 - NL39ss-254)

Enlarged outer diameter (NL3,5spss-254 - NL27spss-254)

Regular outer diameter (NL3ss-276 - NL39ss-276)

Enlarged outer diameter (NL3,5spss-276 - NL27spss-276)

Regular outer diameter (NL3ss-718 - NL39ss-718)

Enlarged outer diameter (NL3,5spss-718 - NL27spss-718)

Treatment surface coating
Through hardened Delta Protekt® base coat (KL100) and top coat (VH302GZ) Surface hardened Surface hardened Surface hardened Surface hardened
Washer hardness*
≥ 465HV1 ≥ 520HV0,05 ≥ 600HV0,05 ≥ 520HV0,05 ≥ 620HV0,05
Corrosion resistance
Minimum 600 hours in salt spray test (according to IS09227) PREN 27** PREN 45** PREN 68** PREN 29**
Bolt grades
Up to 12.9 Up to A4-80 Up to A4-80 Up to A4-80 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

 

* 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.

Washer Hardness

In order to assure the unique wedge locking function of the Nord-Lock washers, the hardness of the mating surfaces should not exceed the hardness of the Nord-Lock washers.


Washer type Range Zinc flake coated
flZnnc – 600
Non coated
Steel washers
(Through hardened)
NL3 – NL130
NL45 – NL130
≥ 465 HV1
≥ 465 HV1
 
Stainless steel washers
(Surface hardened)
NL3ss – NL80ss   ≥ 520 HV0,05
254®SMO washers NL3ss-254 – NL80ss-254   ≥ 600 HV0,05

 

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      

 

Customer success stories

Welcome to the Nord-Lock Group

Secure bolting solutions for your bolting challenges