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D1912-00 – Standard Test Method Technical Guide
📐 Specimen Geometry and Preparation
The test specimen for ASTM D1912-00 (Reapproved 2023) is a cone-shaped sample cut with a steel die or equivalent shearing device, matching the specific geometry outlined in Fig. 2(a) of the standard. Specimens can be taken from any area of the finished hide and are suspended vertically within the cold cabinet by attachment at point C using a standard paper clip. This method applies to all types of finished upholstery leathers, particularly those used in automotive applications.
⚙️ Test Procedure and Apparatus Requirements
The Greuel Rotary Cold-Fold Test Machine is the specified apparatus, utilizing two tangential knurled rollers driven by a chain drive to apply mechanical pressure to the specimen. The critical element of the procedure is the cold cabinet, which must precisely maintain temperatures ranging from −50 °F to +20 °F (−45 °C to −6 °C) with a tight tolerance of ±1 °F (0.5 °C) and allow for easy adjustment in 5° increments. An accurate temperature indicator (±1 °F) monitors the air adjacent to the specimens. During testing, both the conditioned specimen and the entire machine remain inside the cold cabinet to ensure thermal stability throughout the mechanical stress application.
📊 Key Specifications and Significance
This standard provides a reproducible method for evaluating cold-crack resistance, offering results that correlate strongly with the cold impact test and real-world field performance in cold environments. The values stated in inch-pound units are the standard. Below are the critical specifications for the apparatus and environmental control.
| 🌡️ Environmental Parameter | 📏 Standard Requirement | ⚡ Tolerance / Notes |
|---|---|---|
| Temperature Range | −50 °F to +20 °F (−45 °C to −6 °C) | Sustained within cabinet |
| Temperature Accuracy | ±1 °F (±0.5 °C) | Measured adjacent to specimen |
| Adjustment Increments | 5 °F increments | Quick and easy adjustment required |
| Temperature Indicator Accuracy | ±1 °F (±0.5 °C) | Range must match cabinet range |
| 🔧 Apparatus Component | 📐 Detailed Description |
|---|---|
| Test Machine | Greuel Rotary Cold-Fold Machine with chain-driven tangential knurled rollers. |
| Specimen Die | Steel die or shearing device configured to Fig. 2(a) dimensions. |
| Specimen Racks | Rack allowing specimen suspension via paper clip at point C. |
| Stapler | Pliers-type stapler for specimen mounting and fixturing. |
⚠️ Scope Limitation: This test method is strictly for finished upholstery leathers. It explicitly does not apply to wet blue leather, which requires different evaluation methods.
💡 Key Operational Note: For accurate and reproducible results, the entire mechanical test assembly must remain inside the conditioned cold cabinet during the application of pressure. The standard requires values to be reported in inch-pound units.
❓ Frequently Asked Questions
🔍 What specific temperature range is required for the cold cabinet in ASTM D1912?
The cold cabinet must be capable of maintaining temperatures from −50 °F to +20 °F (−45 °C to −6 °C) with an accuracy of ±1 °F (0.5 °C). The temperature must be adjustable in 5° increments.
💡 Can this test method be used for any type of leather product?
No. This method is specifically designed for finished upholstery leathers, particularly in the automotive industry. The standard explicitly states it does not apply to wet blue.
⚡ What machine is specifically cited in the standard for performing the cold-fold test?
The standard specifically designates the Greuel Rotary Cold-Fold Test Machine, which uses two tangential knurled rollers driven by a chain drive.
📌 What are the official units of measurement for this standard?
The values stated in inch-pound units are to be regarded as the standard. Values provided in parentheses (SI units) are for information only.