90KW 50HZ Pit Type Gas Carburizing Furnace Electric Resistance Continuous Gas Carburising Furnace

Pit Type Carburizing Heat Treatment Furnace

Electric Resistance Heat Treatment Pit Type Carburizing Furnace

1. Application

The gas carburizing furnace is a new type energy saving cyclic heat treatment furnace.

It is used for gas carburizing heat treatment of steel machine parts, automobile parts.

Its max working temperature is 1050℃, and the hearth is equipped with one stainless

steel muffle tank. The parts are first loaded in the basket, and then put into the muffle tank.

The atmosphere is drip-in type through the flow meter and dripping pipe.

The fan is mounted in the furnace cover to force an air circulation inside the furnace.

The pit type heat treatment furnace is suitable for all kinds of small and medium-sized parts and long shaft

carburizing, carbonitriding and less than 950℃ no oxidation heating, high temperature annealing

and other heat treatment processes.It has the advantages of strong sealing, high temperature

uniformity, good energy saving and easy operation.

2. Technical Parameters:

3. Structure introduction

This pit type carburizing furnace is comprised of furnace body, furnace lining, furnace cover lifting

mechanism, fan, heating elements, muffle tank, electrical control system and carbon potential control

system.

Furnace body: The frame of carburizing furnace shell is fabricated from 4-12mm

steel plates and 12# sectional steel.

The whole steel structure has good appearance. The external wall of the furnace is painted

with 2 layers of primers, and 2 layers of coating paint. The key part of the furnace is painted

with heat resistant paint.

Lining :pit type furnace is an all-fiber structure. It has the advantages of low heat conductivity,

strong anti-shock capacity, and anti-erosion. The fiber blocks are fixed by round stainless steel

parts. This refractory lining structure has the advantages of low heat conductivity, strong anti-shock

capacity, and anti-erosion. The silicate aluminum fiber resists a maximum temperature of 1200℃.

The refractory fiber is supplied from Shandong. The total lining thickness is 350mm. The furnace

lining adopts 300mm silicate aluminum fiber block as refractory layer and 50mm heat insulation layer.

Furnace cover: The cover is made from ＃30mm A3 steel plate. The heat preservation box of the

cover is made from CrMnN heat resistant castings, and is filled with aluminum fiber. The heat

treatment furnace cover and muffle tank is double-sealed and also water-cooled. The furnace

cover is equipped with water-cooling sealing fan, 3-hole dripper, and exhaust pipe. The drip-in

quantity of the carburizing chemical is controlled by the dripper. The carburizing chemical is

evaporated to become a carburizing atmosphere under high temperature. The inside pressure

is regulated by a pressure regulator. The furnace cover is also preserved with sampling tube,

gas inlet hole, and gas outlet hole for easy installation of carbon potential controller and CO2 analyzer.

Heating elements: 0Cr21AL6Nb spiral-shaped resistance belts mounted in the hearth wall.

The resistance belts are made by special molds to ensure no damage in production. The

resistance belts are fixed to the wall by porcelain nails. The porcelain nails and gaskets are

made of corundum material under high temperature sintering process. The furnace has 1

temperature control zone.

Fan:Installed on the furnace cover. The impeller is made from 310S anti-erosion heat

resistant stainless steel vanes. The fan and shaft is a combination type and is water-cooled.

Muffle tank: 10mm thick SUS310S (0Cr25Ni20) heat resistant steel plate. The muffle tank

and the furnace cover is sealed by asbestos roots. The sealing ring is water-cooled to ensure its service life.

Furnace cover lifting mechanism: The up-down movement of the furnace cover is through

the electrical screw mechanism. On the up-down shaft there are 2 limit switches to prevent damages.

Electrical Control System

Temperature control: The temperature of the electrical resistance furnace is controlled by

JAPAN intelligent temperature controller with PID regulation. It can calculate the ideal PID

parameter, and achieves the most wanted tempeature uniformity and stability.

• This pit type furnace has 1 control zone. The motor moves are necessarily interlocked.
• There is over temperature alarm for each heating zone.
• The components used in the control system are of CHINT or DELIXI brand. The
• components are AC contactor, fast fuse, intermediate relay, travel switch, switches,
• buttons, and indication lights, ammeter, and voltmeter.
• The control cabinet is made according to state standard. And the wires are clearly printed.

4. Supply Scope

5. Carbon Potental Control System

5.1 Main Performance Index

5.1.1 furnace temperature uniformity: ≤±5℃ (effective working area)

5.1.2 temperature stability: ≤±1℃ (instrument control accuracy)

5.1.3 temperature control method: PID power regulation;

5.1.4 carbon potential uniformity: ≤±0.05%CP；

5.1.5 carbon potential stability: ≤±0.02%CP；

5.1.6 carbide uniformity grade: ≤±1 grade;

5.1.7 Effective case depth tolerance: ≤±0.1mm for case depth≤1mm; ±5%

for case depth: ≥1mm; (same bath material);

5.1.8 carbon potential control method: oxygen probe for propane and PID regulation;

5.2 Functions

5.2.1 Temperature control: The temperature control system is based on JAPAN

temperature controller. The temperature system has a high temperature control

accuracy and a high stability. Its temperature control accuracy is ±1℃.

5.2.2 atmosphere carbon potentialk control: The carbon potential control system

adopts anti heat shock oxygen probe, JCT1 carbon potential controller, and imported

solenoid valve to control the carbon potential.

JCT1 carbon potential controller has more than 10 years of field experience.

The potential controller is appropriate for vairous applications. It has a high

control accuracy, and its anti-inteference ability has reached the international level.

The potential controller is able to save 100 processes. The oxygen probe is also set

with carbon deposit burning device.