Optimiranje procesa toplotne obdelave jeklenih polproizvodov v komornih pečeh

Vušnik, Miha (author), Kosec, Borut (mentor)

V podjetju SIJ Metal Ravne d.o.o. so bile v okviru diplomskega dela Optimiranje procesa toplotne izdelave jeklenih polproizvodov v komornih pečeh izvedene meritve temperatur v komorni peči HTO/NTO oz. natančneje HTO, proizvajalca Andritz Maerz z namenom optimiziranja predpisov kaljenja za jeklo PK323, poznano tudi kot SINOXX 4913, X19CrMoNbVN11-1 in W. Nr. 1.4913. S termoelementi vstavljenimi v palici debelin 20 mm in 43 mm smo izmerili realne čase ogrevanja na temperaturo kaljenja in realne čase zadrževanja na temperaturi kaljenja. Na podlagi izvedenih meritev smo izdelali nove predloge za optimiziranje toplotne obdelave, ter jih tudi preizkusili. Palici obeh debelin smo razrezali na pet delov, dobljene vzorce smo pri palici debeline 20 mm poimenovali od A1 do A5, pri palici debeline 43 mm pa od B1 do B5. Vsakemu izmed vzorcev smo predpisali temperaturo kaljenja in čas zadrževanja v peči. Temperature kaljenja so znašale 1110 °C, 1130 °C in 1150 °C, časi zadrževanja na temperaturi kaljenja pa so se razprostirali od 20 min pa tja do 1 h 45 min. V delu je natančno prikazano, na katere mehanske lastnosti sta imeli spremenjena temperatura kaljenja in čas zadrževanja na temperaturi kaljenja vpliv, ter na katere mehanske lastnosti ga nista imeli. Prav tako je obravnavan vpliv temperature kaljenja in časa zadrževanja na temperaturi kaljenja na mikrostrukturo posameznega vzorca. Na koncu je napisana še evalvacija dobljenih rezultatov, ter predlog za izdelavo novega predpisa za kaljenje jekla PK323 v komorni peči HTO.

• Language: Slovenian
• Keywords: Komorna peč, HTO/NTO, toplotna obdelava, PK323, X19CrMoNbVN11-1
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2019
• PID: 20.500.12556/RUL-109261
• COBISS.SI-ID: 1823071
• Publication date in RUL: 29.08.2019

Secondary language

• Language: English
• Title: Optimisation of the heat treatment process of steel semiproducts in chamber furnaces

Abstract

SIJ Metal Ravne d.o.o. authorized the conduction of temperature measurements in HTO/NTO, or more specifically the HTO chamber furnace, manufactured by Andritz Maerz, as a part of the Optimization of the heat treatment process of steel semi-products in chamber furnaces diploma work, with the goal of optimizing regulations regarding the quenching of PK323 steel, also known as SINOXX 4913, X19CrMoNbVN11-1 and W. Nr. 1.4913. Using thermoelements inserted in steel bars of thicknesses 20 mm and 43 mm, we were able to measure the real-world times of heating up to the quenching temperature and the real-world times of holding at quenching temperature. Based on retrieved results we made new suggestions regarding the optimization of the heat treatment and then tested them. Steel bars of both thicknesses were sawed giving us a total of five samples per bar. The samples of 20 mm thickness were named from A1 to A5 and the samples of 43 mm thickness were named from B1 to B5. Each sample was prescribed it´s own temperature of quenching and the time of holding at quenching temperature. The quenching temperatures were 1110 °C, 1130 °C and 1150 °C and the times of holding at quenching temperature ranged from 20 min to 1 h 45 min. The diploma work shows the exact influence of both parameters on the steel´s mechanical properties and the parameters´ influence on the steel´s microstructure. All of the results are then combined and assessed and based off of them is suggestion for an all-new quenching regulation for the PK323 steel inside the HTO chamber furnace.

• Keywords: Chamber furnace, HTO/NTO, heat treatment, PK323, X19CrMoNbVN11-1