Annealing, Hardening, Tempering - Course: Working Techniques of Heat Treatment of Steel. Instruction Examples for Practical Vocational Training: Instruction example 16.4.: Assembly Tools

Annealing, Hardening, Tempering - Course: Working Techniques of Heat Treatment of Steel. Instruction Examples for Practical Vocational Training

		(introduction...)
		Introductory Remarks
		Instruction Example 16.1.: Spiral Spring
		Instruction Example 16.2.: Marking and Riveting Tools
		Instruction Example 16 3.: Flat Chisel and Cape Chisel
		Instruction example 16.4.: Assembly Tools
		Instruction Example 16.5.: Locksmith's Hammer
		Instruction Example 16.6.: Testing Means

Practise the interrupted hardening with subsequent tempering from outside.

Material

Prefabricated hexagon socket wrench, box wrench, screw driver made of tool steel with a carbon content between 1 and 1.1%

Figure

Tools and Devices

Furnace, quenching tank (two pieces), abrasive cloth, file

Auxiliary accessories

Powerful quenching medium (water), mild quenching medium (lubricating oil heated to 150°C), scouring cloth (fat-free)

Previous knowledge required

Manual working of materials

Sequence of operations	Comments
1. Prepare workplace Make working material available	Check for completeness
2. Fire the furnace and bring to nominal temperature	In case of an existing temperature controller, adjust hardening temperature
3. Heat quenching tank with lubricating oil up to approx. 150°C
4. Place tools with the side to be hardened into the furnace and heat up to hardening temperature	Phase 1 Annealing colour: dark cherry-red 770°C
5. After having reached the hardening temperature, keep for approx. 1 minute
6. Dip tools into the quenching tank filled with water, for a short time	Until hissing fades away!
7. Dip tools into the quenching tank with heated oil	Phase 2 Until temperature balance
8. Let tools cool down in air	Phase 3
9. Clean tools, carry out hardness test	File test
10. Grind tools at hardened side blank	Abrasive cloth
11. Heat tools in the furnace once again	Phase 4 Temper colour; purple 270°C
12. After having reached the tempering temperature, cool down tools	Phase 5
13. Clean tools and again carry out hardness test	File test, functional test

Assembly Tools