This is the most likely match for the "-21" suffix in your query, which refers to the 2021 revision of the standard. 分析测试百科网
: It defines standard procedures for conditioning plastic materials before and during testing. Because temperature and humidity significantly affect the physical and electrical properties of plastics, this practice ensures that test results are reliable and comparable across different laboratories.
: It covers various procedures (designated as Procedures A through F) for specific environments, such as standard laboratory atmospheres ( relative humidity) or elevated temperatures. ANSI Webstore ASTM D6182 : Flexibility and Adhesion of Finish on Leather
If your query is specific to leather testing, the correct designation is ASTM D6182 . The latest version is the 2023 revision ( ASTM D6182-23 ANSI Webstore
: This test method evaluates the resistance of finished leather coatings to cracking, delamination, or discoloration when subjected to repeated flexing. Methodology : Technicians use a Bally Flexometer
to flex leather samples for a fixed number of cycles (typically 100 cycles/min). It is widely used for quality control in the footwear, garment, and upholstery industries. Exclusions
: This method does not apply to "wet blue" (chrome-tanned but unfinished) leather. iTeh Standards Which standard are you looking for? I can provide more specific details on the conditioning procedures for plastics Bally Flexometer test for leather finishes.
ASTM D618-21 is the active standard practice for conditioning plastics before conducting physical, mechanical, or electrical tests. This protocol establishes the specific environmental baselines required to achieve reproducible results, ensuring that test data can be reliably compared across different materials and laboratories.
Because the molecular structure of polymers is highly sensitive to ambient temperature and atmospheric moisture, skipping or altering the conditioning phase invalidates standard testing. Authentic copies of the document can be searched and officially acquired via the ASTM International D618-21 Product Page. Why Conditioning Matters in Plastic Testing
Plastics are viscoelastic materials. Their mechanical strength, impact resistance, and electrical insulation properties change depending on the amount of moisture they have absorbed and the temperature of their surroundings.
Moisture Sensitivity: Polyamides (nylons) are hygroscopic. They absorb moisture from the air, which acts as a plasticizer, lowering tensile strength but increasing flexibility. astm d61821 pdf
Thermal History: Polymer chains slowly relax over time. Exposing them to specific temperatures accelerates this relaxation to produce uniform internal stress baselines.
Reproducibility: Without controlling the environment both before and during a test, a lab in a humid tropical region will yield completely different data than a lab in an arid environment testing the exact same raw batch of material. Standard Laboratory Atmosphere
The baseline environment for most plastic testing is the Standard Laboratory Atmosphere. Unless otherwise dictated by a high-precedence material specification, the default parameters dictated by ASTM D618-21 are as follows: Standard Value Standard Tolerance Temperature 23 °C (73.4 °F) ± 2 °C (± 3.6 °F) Relative Humidity
Note: For tests demanding higher precision, tighter tolerances of ± 1 °C and ± 5% RH are actively invoked. The Primary Conditioning Procedures
ASTM D618 outlines several distinct protocols to prepare plastic specimens. The correct procedure depends strictly on the test objectives and the polymer's thickness: 🌀 Procedure A: Standard Atmosphere
This is the most widely utilized default method for general testing.
Thickness ≤ 7 mm (0.25 in): Conditioned for a minimum of 40 hours. Thickness > 7 mm: Conditioned for a minimum of 88 hours.
Objective: Brings test specimens into equilibrium with average room conditions to stabilize mechanical properties. 烘 Procedure B: Elevated Temperature & Desiccation
Conditioning: Exposed to 50 °C (122 °F) in a circulating-air oven for 48 hours.
Cooling: Transferred to a desiccator over anhydrous calcium chloride to cool to room temperature before handling. This is the most likely match for the
Objective: Commonly used to determine the effects of moderate drying or to provide quick, reproducible results for thermosetting plastics. 💧 Procedure C: Severe Humidity
Conditioning: Exposed to 90% relative humidity at 35 °C (95 °F) for a duration of 96 hours.
Objective: Used specifically to evaluate polymer resistance and degradation behavior under severe moisture exposure. 🌊 Procedure D & E: Water Immersion
Procedure D: Immersion in distilled water at 23 °C for 24 hours.
Procedure E: Immersion in distilled water at 50 °C for 48 hours, followed by a rapid water-cooling phase to bring it back to 23 °C.
Objective: Heavily utilized in electrical and high-stress mechanical testing to ensure maximum water saturation. How to Correctly Read ASTM D618 Coded Designations
To condense reporting metrics, ASTM D618 uses a specific shorthand sequence written as Hours / Temperature / Humidity.
Condition 96/23/50: This instructs the technician to condition the plastic specimen for 96 hours at 23 °C and 50% relative humidity.
Condition 48/50/water: This instructs the technician to condition the specimen for 48 hours immersed in water maintained at 50 °C.
Add-on "T": If you see a code like Condition 24/180 : T—180, it means to condition the material for 24 hours at 180 °C, and then actively conduct the physical test at that same 180 °C temperature. Accessing the Official Document Part 5: How to Cite and Use ASTM
To integrate this standard practice into an ISO 17025 certified laboratory framework, a physical or licensed digital file must be purchased. You can easily acquire and view the official documentation using these secure access pathways:
ASTM D618 Plastic Specimen Conditioning Testing - Infinita Lab
Note: ASTM D61821 is not a standard designation within the active ASTM International cannon. Based on user search patterns and typographical analysis, this article addresses both the potential confusion with ASTM D618 (Standard Practice for Conditioning Plastics for Testing) and the structure of obtaining any ASTM standard in PDF format. A specific section addresses how to handle non-existent or mis-typed standards.
Once you have successfully downloaded the correct ASTM D618-21 PDF, proper usage is critical for compliance.
If you are a student or faculty member, your university library may have a site license to ASTM Compass. You can download the PDF for free through your institution's portal.
To summarize:
Final Action Step: Click here to purchase the official ASTM D618-21 PDF directly from ASTM International. (Replace with your affiliate link or direct store link.)
Disclaimer: This article is for informational purposes only. Standard numbers and prices are subject to change. Always verify the active standard on the ASTM website before purchasing. The author is not affiliated with ASTM International.
This procedure provides a standardized approach to measure [property], enabling consistent comparison between batches, suppliers, and formulations. Results support product development, material acceptance, and failure analysis.
This test method describes the procedures to determine [primary property, e.g., tensile strength, flexural modulus, permeability, etc.] of [material, e.g., polymer, composite, coating] under specified conditions. The method applies to laboratory specimens prepared under controlled temperature and humidity and is intended for routine quality control and comparative testing rather than absolute material characterization.