HB 5425-1989 in English

1 Subject Content and Application Scope

This standard specifies the testing method for work zone of heat treatment furnace of aviation workpiece.
This standard is applicable to the testing of the work zone of electric box furnace, shaft-type electric furnace, salt bath furnace, vacuum furnace and special atmosphere furnace.

2 Normative References

GB 9452 "Testing Method for Work Zone of Heat Treatment Furnace"
HB 5354 "Quality Control for Heat Treatment Process of Aviation Workpiece"
GB 3772 "Platinum-10% Rhodium/Platinum Thermocouple Wires and Reference Tables"
GB 2614 "Nickel-Chromium/Nickel-Silicon Thermocouple Wires and Reference Tables"
GB 4993 "Nickel-Chromium/Copper-Nickel (Constantan) Thermocouple Wires and Reference Tables"
GB 4994 "Iron/Copper-Nickel (Constantan) Thermocouple Wires and Reference Tables"
GB 2903 "Copper/Copper-Nickel (Constantan) Thermocouple Wires and Reference Tables"
GB 4989~4990 "Extension and Compensating Cables and Their Alloy wires for Thermocouples"
GB 10067 "Basic Specifications for Electroheat Installations"
JB2251 "Basic Specifications for Resistance Furnace"
JB 3877 "Quenching and Tempering of Steels"

3 Classification of the Insulation Precision of Heat Treatment Furnace

The heating furnace used for the heat treatment of aviation workpiece must be classified according to the insulation precision values listed in Table 1.And the precision class of furnace temperature instruments also shall meet the requirements specified in this table.
Table 1
Class Insulation precision Temperature control precision Instrument precision class Reading of record paper
℃ ℃ No less than No less than
℃/mm
I ±3 ±1 0.25 2
II ±5 ±1.5 0.25 4
III ±10 ±5 0.5 5
IV ±15 ±8 0.5 6
V ±20 ±10 0.5 8

1 Subject Content and Application Scope
2 Normative References
3 Classification of the Insulation Precision of Heat Treatment Furnace
4 Implementation Conditions and Testing Cycle for Testing the Work Zone
4.1 Implementation Conditions
4.2 Testing Cycle
5 Testing Devices for Work Zone
5.1 Thermocouples
5.2 Compensating Wires
5.3 Instruments
5.4 Transfer Switches
5.5 Thermometric Frame
6 Testing Method
6.1 Testing requirements
6.2 Quantity of Testing points and Positions of Temperature Measuring Points of Work Zone
6.3 Testing Temperature
6.4 Testing Procedures
6.5 Repeated Test
6.6 Supplemental Tests
7 Determination of Work Zone
7.1 Analysis of Test Results
7.2 Classification of Insulation Precision
8 Records
9 Signs
10 Management
Additional Explanations: