ASTM A320-L7 is a specification covering bolts, studs, and screws intended for low temperature service. Portland Bolt regularly supplies both plain finish and hot-dip galvanized A320-L7 fasteners to numerous customers in Canada and Alaska. Recently in our Portland Bolt Live Chat, an engineer asked this question as he needed to know what grade of nuts and washers to specify on his project plans.
- Nuts: The compatible nuts for use with A320-L7 are either ASTM A194 Grade 4 or A194 Grade 7 heavy hex nuts. Grade 7 nuts are more readily available and are most frequently used with A320-L7 bolts, but Grade 4 nuts may be used in cases where Grade 7 is not readily available. Since the assumption is that in most cases the A320-L7 bolts will be used in a cold temperature environment, Supplement 3 of the ASTM A194 specification should be specified which requires the nuts to undergo Charpy impact testing which confirms their ability to perform in low temperatures. An “L” is added to the grade marking of these nuts.
- Washers: The compatible washer for use with A320-L7 bolts is ASTM F436. Made from heat treated, hardened steel, F436 washers are capable of withstanding a broad range of environments including low temperature service.
Note: A194 Grade 4 and Grade 7 nuts are typically only available in plain finish. Galvanized Grade 4 or Grade 7 nuts will normally have to be specially made on a per order basis, as plain nuts cannot be used with galvanized bolts.
Could you quote us 120 BOLTS WITH TWO NUTS AS FOLLOWS:
BLT+2N 3″x665 A320/A194-L7/Gr4
We are in Queretaro México. Phone Tel. 442 1955019 Móvil: 5540102069.
Regards.
F. Martínez
@Federico- One of our salespeople will contact you shortly regarding this inquiry.
Can 7M nuts be used with 2HM bolts.
Which combination would be better suited with each other and why..
-B7M Bolts with 7M Nuts
or
-B7M Bolts with 2HM nuts.
Service is not for low temperature.
@Hani- ASTM leaves the decision of which nut-bolt combination is best up to the end user, so either combination is acceptable per ASTM. The down side of using the Gr.7M nut is cost – the 2HM nut will be less expensive, so if you do not need the alloy steel of the grade 7M, then you can save money by using the 2HM.
Which standard in ASME states the bolt torque values for A320 Gr L7 W/A194 Gr 4?
@Hisham- Unfortunately there is nothing within ASME that we are aware of that defines torque values. Torque is unpredictable and can vary significantly. Additionally, the torque needed for one application may not be the same as that needed for a different one. The best way to determine what is needed for your application is to do some testing in a skidmore tension measuring device. That said, we do have a torque chart on our website that can be used for reference, but it again may not be exactly what is correct for your application, so due diligence is required. https://www.portlandbolt.com/technical/bolt-torque-chart/
Good morning ,
Can grade L7 heavy hex nuts be electro plated without being heat treated afterwards.
@Deon- Yes, electroplating would not adversely affect the mechanical properties, so they would not need any additional thermal treatment.
Hello,
I am loking for a small quantity of anchor bolts produced per ASTM A320 Grade L7. I will send through email about details for the dimensions. I need the following informations:
1. Availability in your stock;
2. The price information;
Regards,
Puntsag
@Puntsag- Thank you for your inquiry, we have it and are working on getting it back to you shortly.