Interpretation of ISO 2039 Series Standards: International Guidelines for Plastic Hardness Determination

In the production, R&D, and quality control of plastics and related materials, hardness is one of the core indicators for measuring the mechanical properties of materials, directly related to the reliability, durability, and applicability of products. As the international guidelines for plastic hardness determination formulated by the International Organization for Standardization (ISO), the ISO 2039 series standards unify the test methods, technical requirements, and result expressions of plastic hardness worldwide, providing the industry with a scientific, standardized, and comparable technical basis, which is widely used in chemical, automotive, electronics, medical, and many other fields. This article will comprehensively interpret the ISO 2039 series standards to help you understand their core content and practical value.

I. Basic Understanding of ISO 2039 Series Standards

(1) Core Positioning of the Standards
The full name of the ISO 2039 series standards is “Plastics – Determination of Hardness”. It is a set of international standards for hardness testing of plastics, hard rubber, and related insulating materials. Its core purpose is to eliminate measurement errors between different laboratories and test equipment by standardizing test methods and unifying technical parameters, ensuring the accuracy, paulit ulit na pag uulit, and international comparability of hardness test results, and providing unified guidelines for material R&D, production quality control, product acceptance, and international trade.
(2) Composition of the Standard System
The ISO 2039 series standards are not a single standard but consist of multiple parts. Kabilang sa mga ito, the most core and widely used are Part 1 and Part 2, which correspond to two mainstream hardness test methods respectively. Subsequent parts can be supplemented and improved according to the segmented needs of the industry. The specific composition is as follows:
•ISO 2039-1: “Plastics – Determination of Hardness – Bahagi 1: Ball Indentation Method” specifies the method for determining plastic hardness using a loaded spherical indenter. It is applicable to filled and unfilled plastics, hard rubber, and other materials, and is one of the most commonly used plastic hardness test methods;
•ISO 2039-2: “Plastics – Determination of Hardness – Bahagi 2: Rockwell Hardness Method” specifies the method for determining plastic indentation hardness using a Rockwell hardness tester. Its technical requirements are similar to those of the ASTM D785 standard, and it is suitable for scenarios requiring high accuracy of hardness testing and rapid batch testing;
•Other Supplementary Parts: According to the development needs of the industry, subsequent supplementary parts may be added for hardness testing specifications of specific materials (such as engineering plastics, medical plastics) or specific scenarios (such as high and low temperature environments) to further improve the standard system.
(3) Scope of Application of the Standards
The applicable objects of this series of standards mainly include: various thermoplastics, thermosetting plastics, filled plastics (such as glass fiber reinforced plastics), unfilled plastics, hard rubber, as well as semi-finished and finished components made of these materials; at the same time, they can be used for performance evaluation in the process of material R&D, quality control in the production process, factory acceptance of products, and verification of product quality compliance in international trade. It should be noted that this standard is not applicable to soft rubber, foam plastics, and other materials that are prone to large deformation and difficult to form stable indentations.

II. Detailed Interpretation of the Core Parts of ISO 2039

(1) ISO 2039-1: Ball Indentation Method (Core Focus)
The core principle of the ball indentation method is: press a hardened and polished steel ball indenter of specified diameter vertically into the surface of the test piece under a controllable load, keep it for a specified time, calculate the indentation surface area by measuring the indentation depth, and then calculate the ball indentation hardness (HB) according to the formula “Hardness = Applied Load / Indentation Surface Area” to quantify the material’s ability to resist local plastic deformation. Its key technical requirements are as follows:
1. Requirements for Test Equipment
The test equipment shall meet the following core parameters to ensure test accuracy:
•Indenter: A hardened and polished steel ball shall be used with a standard diameter of (5.0 ± 0.05) mm. The steel ball shall not be deformed or damaged after the test;
•Hardness Tester: It shall be equipped with an adjustable test piece support plate, a non-impact loading device, and an indentation depth measuring device with an accuracy of ±0.005 mm. The frame deformation under the maximum load shall not be greater than 0.05 mm;
•Environmental Control: The test environment shall comply with the requirements of ISO 291 pamantayan (corresponding to China’s GB/T 2918 pamantayan) to ensure stable temperature and humidity and reduce the impact of environmental factors on test results.
2. Standard Test Procedures
To eliminate errors caused by the surface roughness of the test piece and measurement gaps, the ball indentation test shall apply the load in two steps. The specific procedures are as follows:
1.Preloading: Press the indenter into the surface of the test piece with a preload of 9.8 N until a stable indentation depth h0 is reached, which serves as the reference plane (base plane) for subsequent measurements;
2.Main Loading: Select an appropriate test force according to the hardness of the test piece (select from 49 N, 132 N, 358 N, 961 N), apply the load and keep it for 30 mga segundo (exposure time), ensuring that the indentation depth is between 0.15 ~ 0.35 mm; if the depth exceeds this range, adjust the test force and retest;
3.Measurement and Calculation: Measure the indentation depth h after main loading, calculate the indentation surface area according to the standard formula, and then obtain the ball indentation hardness (HB) with the unit of N/mm²;
4.Parallel Testing: To ensure the reliability of the results, multiple parallel tests shall be carried out at different positions of the test piece. The distance between individual indentations and between the indentation and the edge of the test piece shall not be less than 10 mm, and the average value shall be taken as the hardness value of the test piece.
3. Expression Method of Hardness Value
According to ISO 2039-1, the ball indentation hardness value consists of “digital hardness value + HB”, where HB is the abbreviation of Hardness Ball indentation. Halimbawa na lang: 45 HB indicates that the ball indentation hardness of the test piece is 45 N/mm². The larger the number, the higher the hardness of the material and the stronger its ability to resist plastic deformation.
(2) ISO 2039-2: Rockwell Hardness Method
The core difference between the Rockwell hardness method and the ball indentation method is: the reference plane is determined by setting a preload, then after applying the main load, the elastic recovery (depth difference) of the indentation depth is measured, and the hardness value (HR) is calculated in combination with the Rockwell hardness scale. It has higher test efficiency and is suitable for batch testing. Its key points are as follows:
1. Core Principle
Apply the total test force in two steps: first apply the preload to determine the reference plane h0, then apply the main load to make the indenter reach the maximum penetration depth h1. After unloading the main load, the indenter rises to the permanent indentation depth h due to the elastic recovery of the material. The Rockwell hardness value is calculated through the permanent indentation depth h combined with the selected Rockwell hardness scale to reflect the hardness characteristics of the material.
2. Key Technical Requirements
•Indenter Selection: Different types of indenters can be selected according to the material hardness, including steel ball indenters or diamond cone indenters, which shall specifically comply with the standard requirements;
•Load and Time: The preload shall be applied to a stable state, the main load shall be applied for several seconds, and the permanent indentation depth shall be measured stably after unloading;
•Hardness Scale: ISO 2039-2 specifies a variety of Rockwell hardness scales, and the appropriate scale (such as HRM, HRL, atbp.) shall be selected according to the type of plastic to ensure the accuracy of test results.
3. Differences from ISO 2039-1
The core differences between the two lie in the test principle and application scenarios, which are specifically compared as follows: the ball indentation method focuses on general scenarios, can test filled and unfilled plastics, has high calculation accuracy, but the test procedure is relatively cumbersome; the Rockwell hardness method focuses on rapid batch testing, is easy to operate, and is suitable for plastic components with uniform hardness and mass production, and has strong compatibility with the ASTM D785 standard.

III. Corresponding Relationship Between ISO 2039 and National Standards

To adapt to the needs of the domestic industry, China has equivalently converted the ISO 2039 series standards into the national standard GB/T 3398 “Plastics – Determination of Hardness”, among which:
•GB/T 3398.1-2008 (current version) equivalently adopts ISO 2039-1:2001 “Plastics – Determination of Hardness – Bahagi 1: Ball Indentation Method”. On the basis of retaining the core technical clauses of the ISO standard, it has made editorial modifications, such as changing “this part of ISO 2039” sa “this part of GB/T 3398”, using decimal points instead of commas as decimal separators, and replacing the international standards referenced by ISO with corresponding Chinese national standards, which is more suitable for the usage habits of domestic laboratories;
•GB/T 3398.2 corresponds to ISO 2039-2 and also equivalently adopts its core technical requirements to ensure that domestic test results are in line with international standards.
It should be noted that on the basis of the ISO standard, China’s national standard has added some requirements adapted to domestic scenarios. Halimbawa na lang, GB/T 3398.1 mandatorily requires the laboratory temperature control accuracy to reach ±0.5℃ (ISO only specifies ±2℃), and supplements the preloading time correction coefficient for high-filled polypropylene and other composite materials, which is more in line with the mass production quality control needs of domestic electronics, automotive, and other industries.

IV. Practical Application Scenarios of ISO 2039

The application of the ISO 2039 series standards runs through the entire industrial chain of the plastic industry and extends to many downstream industries. The core application scenarios mainly include the following categories:
(1) Material R&D Field
In the process of plastic formula R&D, the hardness of materials with different formulas (such as different plasticizer contents and different filling ratios) is tested through the ISO 2039 standard to optimize the formula design and achieve the matching between material hardness and usage requirements. Halimbawa na lang, when developing plastics for automotive interior parts, it is necessary to test the hardness by the ball indentation method to ensure that the material has a certain hardness to resist wear and a certain toughness to avoid brittleness and fracture.
(2) Production Quality Control Field
This is the most core application scenario of ISO 2039. In the production process, the hardness of plastic semi-finished products and finished products is tested by regular sampling to judge whether the production process (such as injection molding temperature, molding pressure) is stable, find unqualified products in time, and avoid batch quality problems. Halimbawa na lang, in the production of plastics for electronic and electrical casings, the Rockwell hardness method is used for batch testing to ensure that the hardness of the casing meets the standard and can protect internal components from impact damage.
(3) Product Acceptance and International Trade Field
In the procurement, acceptance, and international trade of plastic products, the ISO 2039 standard is the core quality judgment basis agreed by both parties. Supply and demand parties can clarify the hardness index requirements according to this standard, and verify whether the product hardness meets the contract agreement through testing by third-party laboratories in accordance with standard methods, so as to avoid quality disputes caused by inconsistent test methods. Halimbawa na lang, the casings of power tools exported to the EU need to be tested for Rockwell hardness in accordance with the ISO 2039-2 standard to ensure compliance with relevant EU access requirements.
(4) Special Industry Applications
In industries with strict requirements on material performance such as medical treatment and children’s toys, the ISO 2039 standard can be combined with other special standards to achieve dual verification of material safety and reliability. Halimbawa na lang, medical catheter materials need to be tested for hardness through ISO 2039-1, and combined with the ISO 10993 series of biocompatibility standards to ensure that the catheter has moderate hardness, which is not only easy to operate but also will not cause damage to human tissues; materials for the biting area of children’s toys need to be combined with the ISO 8124-1 standard to test the local hardness gradient through ISO 2039-1 to ensure the safety of use.

V. Explanation on ISO 2039 Certification

It should be clearly noted that the ISO 2039 series standards themselves are not “certification standards” but “test method standards”. Enterprises do not need to apply for “ISO 2039 certification”, but ensure that the product hardness indicators meet relevant requirements by carrying out hardness testing in accordance with this standard. Gayunpaman, in actual production and operation, enterprises can combine the ISO 9001 quality management system certification, integrate the test requirements of the ISO 2039 standard into the quality management system, and improve the quality control level. The specific relevant points are as follows:
(1) Requirements for Testing Laboratories
Laboratories carrying out tests in accordance with the ISO 2039 standard shall be equipped with corresponding test equipment (such as hardness testers and indenters meeting standard requirements), the laboratory environment shall meet the requirements of temperature and humidity control, and test personnel shall receive professional training and be familiar with standard procedures to ensure standardized test operations and accurate results. Qualified enterprises can apply for Laboratory Qualification Certification (CMA) or Laboratory Accreditation (CNAS) to enhance the credibility of test results.
(2) Coordination with ISO System Certification
When applying for ISO 9001 quality management system certification, enterprises can incorporate the test requirements of the ISO 2039 standard into links such as “product realization” at “monitoring and measurement”, establish a complete hardness test process and record management system, and ensure that the hardness test of each batch of products is traceable. This can not only improve the enterprise’s quality management level but also enhance customers’ trust in product quality.
(3) Correction of Common Misunderstandings
Many enterprises confuse “testing in accordance with the ISO 2039 pamantayan” with “ISO 2039 certification”. It should be clearly stated that ISO 2039 only specifies test methods and has no special certification projects; the core goal of enterprises is to ensure that product hardness meets their own product standards, customer requirements, or industry specifications through testing in accordance with this standard, and the test report can be used as evidence of qualified product quality.

VI. Value and Significance of ISO 2039 Mga Pamantayan

As the international general guidelines for plastic hardness determination, the core value of the ISO 2039 series standards lies in “unification, standardisasyon, and comparability”. Their specific significance is reflected in three levels:
(1) For Enterprises: Improve Quality Control Level and Reduce Quality Risks
The standards provide enterprises with scientific and standardized test methods, helping enterprises accurately grasp the hardness performance of materials and products, optimize production processes, and reduce problems such as product scrapping and customer complaints caused by unqualified hardness; at the same time, the unified test methods facilitate enterprises to carry out internal quality control and supplier quality audits, and improve the overall quality level of the supply chain.
(2) For the Industry: Standardize Market Order and Promote Technological Progress
The popularization and application of the standards have eliminated measurement errors between different enterprises and laboratories, established a unified industry quality evaluation system, and avoided disorderly market competition caused by inconsistent test methods; at the same time, the update and improvement of the standards will also promote technological progress in related fields such as plastic material R&D and test equipment manufacturing, helping the high-quality development of the industry.
(3) For International Trade: Break Technical Barriers and Promote Global Circulation
As international standards, ISO 2039 provides a unified quality judgment basis for global plastic product trade, helping enterprises break technical trade barriers between countries, ensuring that the hardness test results of China’s plastic products are internationally recognized when exported, reducing the risk of trade frictions, and promoting the global circulation of plastic products.

VII. Buod

The ISO 2039 series standards are the core international guidelines in the field of plastic hardness determination. Their core consists of two key parts: the ball indentation method (ISO 2039-1) and the Rockwell hardness method (ISO 2039-2), which unify test equipment, procedures, calculation methods, and result expressions, adapting to test needs in different scenarios. These standards are not only important tools for enterprises to carry out quality control and product R&D but also key supports for standardizing industry order and promoting international trade.
For enterprises, in-depth understanding of the core requirements of the ISO 2039 standards and integrating them into the entire production and quality control process can not only improve the stability of product quality but also enhance the core competitiveness of enterprises; for the industry, popularizing the application of standards and promoting the in-depth adaptation of standards to domestic scenarios can help the high-quality development of the plastic industry and achieve seamless connection with the international market. In the future, with the continuous innovation of plastic materials and the continuous expansion of application scenarios, the ISO 2039 series standards will also be continuously improved to provide sustained technical support for the development of the industry.

Our Product GA-1035 Plastic Ball Indentation Hardness Tester meets this standard.

 

GA-1035 Plastic Ball Indentation Hardness Tester

I.Product manufacturing and inspection standards.
1. JB/ t741-94 “technical conditions of plastic ball indentation hardness tester”
2. JJG 369 — 1993 “verification rules for the hardness of plastic ball indentation”

II.Applicable test method standard.
1. GB3398.1-2008 plastic hardness test part I: ball indentation method
2. Iso2039-1:2001 plastic hardness test part I: ball indentation method

III.Main technical indicators.
1. The test load is divided into six levels: 9.8N(preloaded)49N, 132N, 358N, 612N, 961N.
2, steel ball head: Φ 5 mm, Φ 10 mm
1. The indentation depth indicates the minimum dividing value: 0.001mm.
2. Maximum allowable height: 10mm.
3. Head to machine wall distance: 55mm.
4. Indication accuracy: + o + 4%.
5. Timing range: 10~90s, timing accuracy + + 0.1s.
6. Effective measurement range: 0.150-0.35mm.
7. Deformation of frame: no more than 0.05mm.
8. Equipment weight: 45kg.
9. Equipment external dimension (mm) : 330 * 220 * 425.

IV.Range of application
This instrument can be used to measure the hardness test of plastics, plastic materials and other industries, and can print the data.The machine adopts color touch screen technology to make the operation simpler, more intuitive and more beautiful.This product is our patented product.

V.Structure composition and principle.
It is mainly composed of main engine, pressure head, loading device, deformation acquisition system, micro-processing system and so on.
Micro – processing system deformation acquisition system.
Color crystal touch screen head.
Plastic hardness refers to the ability of plastic materials to resist another rigid object that does not produce elasticity and plastic deformation.
The hardness test of plastic ball indentation is to press the steel ball with the specified diameter to the surface of the sample under the action of the test load, and then read the depth of the indentation after a certain period of time.The hardness value is obtained by calculating or checking the table.
1.The thickness of the sample is not less than 4mm. The adjustable range of the loading speed is 2-7 mga segundo, usually 4-6 mga segundo, and the loading time is 30 seconds or 60 seconds.The load size should be selected according to the expected hardness of the sample.Instead, take a smaller load.If the hardness of the sample cannot be predicted, it must be gradually upgraded from the smaller load, so that the ball pressure head and sample will not be damaged.Generally, the test can be carried out by selecting the load according to the sample requirements.
2, the ball indentation hardness refers to regulation of the diameter of the steel ball, the test load under the action of vertical pressure into the surface of the sample, keep a certain amount of time, per unit area of average pressure Kgf/was or N/was said.
Its expression is:
H = 0.21p / 0.25 (H -0.04) (kg/ mm2)
P – load (kg)
H – indentation depth (mm)
D – ball diameter (mm)
PI PI –
Tala: h = h1-h2
H1: pressure depth of sample load (mm);
H2: rack deformation under test load (mm)

VI.Sample requirements.
1. The sample should be uniform thickness, smooth and smooth surface, no bubble, no mechanical damage and impurities.
2. The thickness of the sample should not be less than 4mm, and the sample size should ensure that the distance between each measuring point center and the sample edge is not less than 10mm, and the distance between each measuring point center is not less than 10mm.The recommended sample size for 40 * 40 * 4 mm or Ф 50 x 4 mm.

Product link:

https://www.gonoava.com/product/ga-1035-plastic-ball-indentation-hardness-tester/

Contact:

Mag-email: arlenliu@gonoava.com
WhatsApp: 0086 18670728798(We chat)
If you have any questions you can send me a message or email.