Equipment Introduction

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Equipment for bright Martempering
Our line for bright Martempering consists of the following major units.

(1) Strip handling equipment:
Composed of pay-off reels, take-up reels, tension controller,speed controller and drive system.
(2) Hardening furnace:
The furnace shown is of gas-tight type which can prevent the treating strips from being oxidized or decarburized and its temperature in theheating chamber is automatically controlled within +1°C to render the hardened strips with uniform mechanical properties.
 
(3) Quenchant bath:
A molten lead is used as a quenchant which enables the strip microstructure to be transformed isothermally, making the treating procedure of Martempering & Austempering available.
 
(4) Levelling furnace:
A electrically heated leveling furnace is adapted in order to get very flat stripsreducing the dish of the strips to 0.5 Mm per mm of strip width.
(5) Tempering furnace:
The furnace has an atmosphere seal and is fitted with powerful circulation fans.By means of this powerful convection ststem, it is possible to achieve extremely low tensile strength tolerances, say within+15N/mm for 300m/m wide strips.
(6) Atmosphere plant:
The atmosphere plant, which is mainly composed of an ammonia cracker, a hydrogen and nitrogen mixer, adsorber, and hydrogen control unit shown in Fig,7, is used to supply the hardening furnace and the complete line with suitable atmosphere in order to prevent the strips from being oxidized or decarburized and to produce the hardened strips with bright white or bright blue surface color.
 
(7) Power and control center:
Incorporating temperature control and recording facilities .
The accurate and automatic control system in the power and control center enables the heat-treating line to produce the strips with optimal mechanical properties and to guard the equipments against being damaged.

Characteristics
Quenching in lead, followed by microstructural transformation in an air jet cooler can offer the steel strips with the best mechanical properties, such as:

(1) Tensile strength unfiormity, within±1%.
(2) Better planeness
(3) Better bending fatigue strength and impact strength (please refer to Table 1.)
(4) Good surface finish.
(5) Strip thickness/width ratio 1:2000, without planeness and tensile strength tolerances being affected.