
MNK ENGINEERING TOOLS
Engineering Calculators
Metal weight, Montenegro working days and EUR–USD–CNY reference conversion in one practical workspace.
Planning Results for Industrial RFQs
These calculators provide preliminary planning values. Confirm material density, dimensional tolerances, statutory working-day treatment, exchange-rate basis and final commercial terms before placing an order.
Send Your Technical Inquiry
Send the grade, product form, dimensions, quantity, documentation requirements and delivery destination.
Engineering Unit Converter
Length, mass, pressure / stress and temperature.
A decimal point or comma is accepted. Do not use thousands separators. Results are displayed to 12 significant digits; intermediate values are not rounded.
Conversion references: NIST SP 811PREN Reference Calculator
Enter chromium, molybdenum and nitrogen as mass percentages from the material analysis.
PREN = %Cr + 3.3 × %Mo + 16 × %N
This version uses the Cr-Mo-N formula only; tungsten is not included.
Decimal dot or comma accepted. Unknown content is not zero: enter 0 only when confirmed.
Calculated PREN reference value
Stainless steels only. This index supports rough comparison; it does not establish service life or suitability for seawater. Welding, surface condition and the operating environment need separate assessment.
Hardness Reference Converter
Approximate conversion for homogeneous non-austenitic carbon, alloy and tool steels only.
Use only for preliminary comparison. Not for austenitic or duplex stainless steels, hardmetals, non-ferrous alloys, coatings, or non-homogeneous/case-hardened parts. The estimate does not replace the specified acceptance test or a material certificate.
Test basis: macro-Vickers HV; Brinell HBW with a 10 mm tungsten-carbide ball and 3000 kgf force; Rockwell C with a diamond cone and 150 kgf total force. HBS and microhardness are not supported. WC-Co/HRA conversion is not supported: this tool has no separate validated dataset for it.
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Method, source and limitations
Independently written calculation using equations A1.1 and A1.3 of ASTM E140-12b(2019)e1. HV and HBW are correlated with HRC; reverse conversions use numerical inversion. HV/HBW conversion combines both correlations. No conversion table is reproduced. Results may differ from tabulated values. Converted results are rounded to whole numbers; exact half ties round to the even integer.
Keep the original measured scale, test load and material condition when preparing an inquiry. Material composition and treatment affect the comparison; no universal error bound is claimed. This tool is not a certification or an ASTM conformity statement.
Calculation takes place in your browser; the entered hardness value is not sent by this module.