ASME/ISO/MSS Flange - Torque
This screen is devoted to lubricant selection, load specification and resultant torque values, and tool pressures for your chosen RSL model wrench.
You may choose between two formula for calculating the torque value. Either use the Farr's formula based on a known lubricant with a known co-efficient of friction. This is labelled "Using Coefficient". If you choose this methodology you must select either a lubricant from the drop down list, or enter an alternative lubricant under "User Specified", and specify your own known co-efficient friction of your chosen lubricant. The Friction value is displayed immediately to the right of the lubricant chosen.
The alternative method available to you is to use the "Nut Factor" formula. If this is your choice you will not be able to choose a lubricant. Instead you will need to enter the "Nut Factor" into the appropriate labelled box.
The Calculator will then perform up to three torque calculations based on the loading conditions as follows:
No 1 is the minimum bolt stress and bolt load required to seal this flange joint for the conditions entered based on the ASME 8 code. This value was calculated from the data entered and shown on the previous screen. The calculations also give the percentage of bolt material yield as a quick visual check that the data is meaningful.
No 2 allows you to specify a bolt load or bolt stress that you require to achieve in the bolted joint. The data can be entered in either metric or imperial units but care should be taken to make sure the data is entered correctly. As an alternative you can also enter the required bolt load as a percentage of the yield strength of the chosen bolt material. The default is set to zero. If left at zero no tool pressure values will be displayed.
No 3 displays our recommendation for bolt load and stress based on Hydratight custom, practice, experience and knowledge. If no value is displayed this is because we have insufficient experience of this flange to make a recommendation. If you require further advice please contact Hydratight.
The Calculator will also display suitable RSL tools for this application as well as the appropriate hydraulic tool pressure(s).
Firstly, choose the bolt load you wish to use for the recommendation. You may choose between the loadings using the drop down box called Select Calculation. Making this choice will create a list of RSL tool models in the Select Tool window.
The tool selection options are based on the wrench only being required to tighten bolts or studs. If you alter the default No setting in the box Will the wrench be used for break out? to Yes, the tool selection options may be modified to reflect the higher torques required for stud or nut break out.
Select whether your tool will be a square drive or fitted with hexagon cassette by choosing between the two options in the box labelled Tool Type.
You should now select the RSL model you have or plan to have by clicking on the RSL model in Select Tool box. The housing model now will be displayed in the window labelled Housing, and the outline drawing on the right hand side of the screen of the chosen RSL model will now be dimensioned. This will help assist you if you need to confirm tool fit.
NOTE! If the torque required is beyond the capacity of the RSL tool range the message ‘No suitable wrenches. Please contact Hydratight’ will appear.
The Calculator will now display the hydraulic pressure to be used with your chosen RSL. The pressure displayed is based on your bolt load option chosen in the Select Calculation box using the selected lubricant. If you wish to change your choice of Lubricant, Bolt Load, Bolt Load option, or tool type you will need to re-enter the data as required. For a new calculation and pressure you will always need to re-confirm your tool selection in the Select Tool box.
Min Bolt Length. This is the bolt length required for your chosen flange using a hydraulic torque wrench. The length displayed is based on a weld neck to weld neck connection.