Technical parameters and calibration cycle of stainless steel standard weights

Definition and purpose:

Stainless steel standard weight is a physical measuring tool made of stainless steel material, with precise known mass and specified shape.

Main purpose: Used for transmitting quality values and calibration in quality measurement/Calibrate weighing instruments (such as scales, scales), conduct quality measurement comparisons, and serve as quality benchmarks in laboratories and production processes.

Classification and Level:

According to international recommendationsOIML R 111In accordance with national standardsJJG 99-2022According to the "Verification Regulations for Weights", weights are classified according to accuracy levels, and stainless steel weights usually cover the following levels:

Note:ETheFThe grade has strict requirements for magnetic susceptibility and magnetism, and non-magnetic stainless steel must be used.MThe level requirements are relatively relaxed.

Material and Characteristics:

The core performance of stainless steel weights lies in their material stability, corrosion resistance, and weak magnetism.

Material

Austenitic stainless steel: such as304 (0Cr18Ni9)The316/316LIt has good corrosion resistance and machining performance, and can achieve low magnetic or non-magnetic state through special treatment (such as solid solution treatment), making it suitable for manufacturingETheFCommon materials for grade weights.

martensite/Precipitation hardened stainless steel: such as440CThe17-4PHHigh hardness and wear resistance, but strong magnetic properties, usually used for applications with low magnetic requirementsMGrade weights or occasions requiring high hardness.

Key characteristic requirements:

Magnetism: The magnetic susceptibility and magnetism of the weight must be controlled within the specified limits to avoid magnetic interaction errors on the balance.E/FThe level requirements are extremely strict (magnetic susceptibility x) ≤ 0.00015Polarization intensity ≤ 25 MT）.

Density: usually adjusted to8000 kg/m³ (or7950-8050 kg/mTo facilitate air buoyancy correction within a range of (3). Some high-precision weights will be labeled with their actual nominal density.

Surface quality: It should be smooth and flat, without burrs, sand holes, scratches, or rust. High grade weights require mirror polishing to reduce adsorption and corrosion.

Hardness and wear resistance: The surface needs to have sufficient hardness to resist wear during normal use.

Technical parameters and requirements:

Quality tolerance: Each level of weight has its allowable error（MPE）The smaller the value, the higher the level. For example, one1kgofF1The allowable deviation of the grade weight is much smaller thanM1Grade weight.

Shape and Structure:

Milligram group weight(1mg - 500mg)Usually in the form of a sheet with corners or tweezer grooves.

Gram group weight(1g - 50g)Mostly hexagonal, cylindrical, or cylindrical with a knob.

Kilogram group weight(≥1kg)Generally cylindrical in shape, with handles or knobs. The interior can be solid or hollow (with adjustment chamber).

Marking: The nominal mass value and mass unit should be clearly marked on the weight body. High grade weights will also be marked with factory numbers, manufacturers, and other information.

Adjustment chamber: for larger masses (usually ≥)1g）The weight allows for an adjustment chamber for adding/Reduce materials to precisely adjust quality. The adjustment chamber must be sealed with a plug of similar density to the weight material, and there must be no mass leakage after sealing.

Usage, storage, and maintenance:

Proper operation and maintenance are key to ensuring the long-term accuracy of weights.

Operation

1Special tools (such as weight tweezers, gloves, lifting ropes, etc.) must be used for handling, and direct contact with hands is prohibited to prevent sweat and stains from corroding the weight and changing its quality.

2Handle with care to avoid collisions, scratches, or falls.

3Before and after use, clean the surface with a soft dust-free cloth or suede.

Cleaning:

For ordinary stains, they can be wiped with alcohol or neutral detergent and immediately wiped dry with a dry cloth.

For stubborn stains or slight oxidation, a specialized stainless steel weight cleaning agent can be used, and the operation should be strictly followed according to the instructions.

It is strictly prohibited to use strong acids, strong alkalis, or cleaning agents with abrasive properties.

Storage:

1Store in a dry, clean, and non corrosive gas environment.

2When not in use for a long time, a small amount of anti rust oil should be applied and stored in the original box.

3Weights of different grades and materials should be stored separately to avoid collision with each other.

Periodic verification:

As a measuring standard, weights must be regularly sent to legal metrological verification institutions or qualified laboratories for periodic verification according to their frequency of use and grade, to ensure the accuracy and reliability of their measurement values. The verification cycle is usually1Year.

Procurement and Selection Guide:

1Clear level requirements: Based on the tested instrument (balance)/The accuracy requirement for the scale is to choose a higher grade or an appropriate weight grade.

2Confirm material and magnetism: For high-precision scales (over ten thousandths), it is necessary to choose non-magnetic stainless steel (such as316LofE/FGrade weights to avoid magnetic errors.

3Inspection certificate and identification: Legitimate products should be accompanied by a factory certificate of conformity, and a calibration certificate or verification certificate issued by a metrology institution can be provided. The certificate should include information such as actual quality values, uncertainty, density, magnetic parameters, etc.

4Inspection process: Check the surface smoothness, corner treatment, marking clarity, and sealing of the adjustment chamber of the weight.

5Choose a reputable manufacturer: select one with a 'Manufacturing Measuring Instrument License' A legitimate manufacturer.

Common standards and specifications:

International:OIML R 111-1 & R 111-2 (International Organization for Legal Metrology)

China:JJG 99-2022Verification Regulations for Weights/ JJF 1834 - 2020General Technical Requirements for Non Automatic Weighing Instruments

Material standards:GB/T 1220Stainless Steel Rod

Through the above information, you can comprehensively understand the technical points of stainless steel standard weights, and provide professional basis for their correct selection, use, and maintenance.

Technical parameters and calibration cycle of stainless steel standard weights