JB/T 8133.18-2017 in English

VALID

Test methods for physical and chemical properties of electric carbon products - Part 18: Linear expansion coefficient

Issued on:2017-04-12
Implemented on:2018-01-01
File Format:PDF
Delivery:Via email within 1~3 business days

Price(USD)： $149.00
$145.00

Standard No:	JB/T 8133.18-2017
Document status:	VALID
Title in English:	Test methods for physical and chemical properties of electric carbon products - Part 18: Linear expansion coefficient
Title in Chinese:	电炭制品物理化学性能试验方法第18部分：线膨胀系数
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 1~3 business days
Issued on:	2017-04-12
Implemented on:	2018-01-01
ICS Classification:	29.120-Electrical accessories
Chinese Classification:	K16-Electrical carbon product
Professional Classification:	JB-Machinery
Related Keywords:	linear expansion coefficient α test methods linear expansion coefficient introduction technical background linear expansion test process

Introduction

Technical Background of the Standard

As Part 18 of the JB/T 8133 series of standards, this standard systematically specifies for the first time the test method for the coefficient of linear expansion of electrical carbon products. With the expanding application of graphite materials in industrial fields such as sealing and electrical conductivity, accurately measuring their thermal expansion properties is of great significance to product design and safe use.

Core test requirements

Test elements	Technical requirements	Allowance deviation
Specimen size	Diameter 4-10mm, length 50-60mm	±0.05mm
Surface roughness	Ra≤1.6μm	Parallelism error≤0.06mm
Heating rate	2℃/min below 350℃, 5℃/min between 350-1000℃	Furnace temperature gradient±2℃

Key equipment configuration

The standard requires the use of a quartz linear dilatometer in conjunction with the following devices:

Temperature range: Room temperature-1100°C
Displacement sensor: Linear digital, resolution 0.01mm
Protection system: Inert gas/vacuum environment (must be enabled above 200°C)

Key points of the test process

Take the graphite sealing ring test as an example:

Process the sample according to JB/T 8133.1 to ensure the parallelism of the end faces
Place the sample in the medium temperature zone of the quartz tube holder and position the thermocouple in the center
In the 350℃ stage, use a slow heating rate of 2℃/min and record the change in ΔL.
When testing at 1000℃, argon protection must be continuously introduced.

Data Processing Specifications

Calculation formula for linear expansion coefficient α:

α = (L_t-L₀)/[L₀×(T_t-T₀)]

Measurement requirements for each parameter in the formula:

Use a 0.01mm precision micrometer for length measurement
Temperature constant time ≥ 30 minutes
More than 3 valid samples need to be tested

Implementation Suggestions

1. Equipment Selection: Digital dilatometers with automatic temperature compensation are preferred.
2. Specimen Preparation: Diamond tooling is recommended to ensure surface quality.
3. Abnormal Handling: When the test curve shows nonlinear changes, the oxidation condition of the sample should be checked.

More samples: JJG 21-2008 YD/T 3934-2021 JC/T 2453-2018

Sample only — not a preview of JB/T 8133.18-2017