Vulcan entered the long bar quench and temper market and now the Heat Treating division is the largest long bar, induction heat treater in the world with annual. Caution: All material included in this chart is advisory only, and its use by anyone is voluntary. In developing this information, Fastenal has. Esparragos #B7 #Cadmiados #Fluorocarbonados #Galvanizados #Quito # Ecuador [email protected]

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This is a different grade of material than A Grade B7. There are some significant differences in both the mechanical properties and the testing requirements of AB7M and AB7. The most notable difference from a manufacturing perspective is that when providing AB7M bolts, every individual bolt or stud in the lot must be hardness tested.

While AB7 is specified relatively often in the construction industry, AB7M is a specification that is not seen as regularly. This makes it important to understand the differences between the two specifications so that the correct material is ultimately provided.

ASTM A B7 vs. A B7M – Portland Bolt

However, I find some contradicting answers when searching around, can it be both depending on the heat treatment esparrgos consequent microstructure? Your advise would be much appreciated. It is made from alloy steel which is a ferritic steel. There are demagnetization techniques, but normal, off the shelf B7 and B7M bolts will be magnetic.

Usama- In order to change B7 to B7M, you would need to temper the bolts to a lower hardness. I am working in petroleum refinery. As we know B7M is having less strength but low hardness than B7, how it is helping us. I understand we could not tighten the internals bolts B7M in our case and it should withstand in extreme process condtion i.

Saddam- Your supplier should have material test reports and documentation to show how the material was manufactured. Regardless, the hardness testing should be completed after the final heat treatment. ASTM A is a low carbon steel, low strength, general purpose bolt standard. We have strength and chemical summaries on the individual ASTM summary pages on our website. Martin- For all intents and purposes, they are the same.

The differences can come if the item is being used in nuclear or special applications, then there might be some additional requirements, but we are less familiar with those.

Jonathan — for materials that are heat treated, the reason is that the heat treating has hard time penetrating all the way to the center of the steel, so the larger your material gets, so weaker the center section might be. Same as baking a cake — if it is large, the center never gets completely done.

I have a query. Which is category for Mushroom Head roofing bolt without neck to be manufactured? Manickam- We manufacture carriage bolts and timber bolts, both which have a round, curved head. We are not familiar with a bolt specifically called a mushroom head. As for why the larger bolts are 8tpi, the threads are more shallow than their UNC counterparts, which creates a larger thread root area.

The downside is that the shallow threads are more susceptible to damage and thread stripping in some situations. Osama- We are sorry, but we are not familiar enough with the requirements of sanitary lifting stations to know if B7M bolts are allowed. Neil- A B7M does not specifically cover washers, although I guess theoretically you could make them from the same material. I see no issues using the same bolting material to make washers for use here.


That said, ASTM F washers are an off the shelf, very common washer that may provide the same benefit at a much lower cost. At wellhead platformB7 bolts used instead of B7Mis there any big issue.

Enviornment is a little bit corrosive. Jayant- B7 and B7M bolts are chemically identical, so they would both have the same corrosion resistance, which is negligible. However B7 and B7M bolts re not mechanically identical.

Esparragos ASTM A193 Gr. B7, 2 Tuercas A194 Gr 2h Bolt

B7 bolts are stronger, but rated for lower temperatures than B7M. You will need to consult the project engineer and get their approval for the substitution. May you help me about correlation Bolt Tensile Strength vs Pressure? Is there any calculation about it? Ferry- Apologies, but we do not have any engineers on staff, and do not have the expertise to answer this. Sorry we could not help. At least Can We say the stud bolts are stronger than machine bolts?

Thanks a lot, Ashkiani. Ashkiani- The only difference is that the machine bolt has a head, and the stud bolt does not. Mechanically, assuming that they are the same grade, they will be identical. Machine bolts sometimes fare better during wedge tests due to the forged head, but we would not say that one is stronger than the other. It will depend on how they are being used and what the engineer designed for. Ashkiani- A stud bolt is a threaded stud with no head, whereas a machine bolt has a forged head on one end.

Grupo Kazerooni – Varilla Roscada, esparragos B7, B16, Monel y mas Varilla Roscada

Washers can, and are sometimes used with both stud bolts and machine bolts. It is up to the designer or engineer if they are required or not. F is the recommended washer for A B7 bolts, and can a mild steel washer be espsrragos for A B7?

Esparraos mild steel washer is not hardened and will likely not perform as well with B7 bolts or studs. Vijay- Of those, A B7 is the closest to grade 8. It is not exact, but the closest of the four grades you listed.

We have a valve with Grade B7 bolts that need to be change out, we will need longer bolts when eslarragos back together. Will Grade 8 bolts work as a replacement? There are some differences between the two. As for the studs, same answer, make sure an engineer is ok with the substitution as there may be pros and cons to espsrragos the switch. We have B7M thread rod and we cut it to esparraos required short length stud bolts did now it is again required heat treatment. While as per clause 6.

Waqas- You are correct, no further processing is permitted after final heat treatment. Even a simple cutting process will require an additional heat exparragos process. What can be the risks if we accept it as is? However, espafragos do not have any engineers on staff, so we cannot speak to all the possible risks, but what we can say is that 2HM nuts are quite specialized, and I would assume there is a good reason that they were originally specified. Maroof- A B7M is an alloy steel bolting standard, whereas A is a hot dip galvanizing standard, so they are two, very different specifications.


What is the difference between B7M and B7M comply to nace mr Is it just the hardness we are talking abt? Ari- There are some similarities in tensile and yield, but they are not identical.

A193 Esparragos B7 A194 Tuercas 2h Stud Bolt

You can find summaries for both ASTM standards on our website. Any substitution should be run by an engineer. Jugal — I am sorry, but we are unable to answer that question. You may need to contact an engineer or metallurgist. Tauseef- We are not familiar with BS washers, so I cannot compare those. Hi, I would like to clarify if the commonly referred bolt classes class 1,class 2 is of the same meaning segregating b7 from b7m? Class 1 refers to lower strength materials whereas class 2 refers to higher strength, strain hardened material.

B7 and B7M are two separate grades within A that are made from alloy steel.

Is it possible to use A Gr. B7M bolt on an SSL flange. If not which is the suitable bolt material A Gr. B16 or A Gr. The design temperature of the tank is 85 deg C only. Tauseef- F washers are the recommended washer for A grades B7 and B7M, if washers are needed. What standard is the nut compatability chart listed on your website pulled from?

The A nut chart we created based on common industry practices. B7 and B7M Bolts have their own equivalent nuts which is 2H and 2HM respectively, is it allowoed to interchange these nuts? If washers were to be required what would it be? Richard — 2H and 2HM nuts are not the same strength 2HM are lower strength, but rated for higher temperatureso I would recommend against substituting one for the other. It is usually used in higher temperature applications. I cannot recommend one or the other for your application, you would need to consult with the project engineer.

Mehul — We do not heat treat in house, so you will need to contact a heat treat facility to get specifics about their process.

While no other indication is made, would these studs have to be coated, zinc plated, etc.?? Noble — I am sorry, but we cannot make any specific recommendations regarding whether or not you would need a coating. You will need to consult with the project engineer.

Islam — You would need to get approval from the project engineer to change bolts. B7 and B7M are very different. The corresponding nuts standards are A grade 8M and F group 2. There are no ASTM standards for stainless esparrxgos. We have summaries for both ASTM standards on our website. B7 2-can galvanize hex nut A GR.