INFLUENCE OF COOLING RATE DURING QUENCHING ON IMPACT TOUGHNESS OF A HOT-WORK TOOL STEEL AT AMBIENT TEMPERATURE AND AT 200 °C

• Main Author: Henrik Jesperson
• Format: Article
• Language: English
• Published: Univerzity of Zilina. Faculty of Mechanical Engineering 2013-05-01
• Series: Materiálové Inžinierstvo
• Subjects: Tool steel; toughness; temperature; heat treatment; impact testing; quenching rate; cooling rate
• Online Access: http://ojs.mateng.sk/index.php/Mateng/article/view/83
• ISSN: 1335-0803; 1338-6174

<span style="font-family: Times New Roman; font-size: small;"> </span><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><span style="mso-ansi-language: EN-GB;" lang="EN-GB"><span style="font-size: small;"><span style="font-family: Times New Roman;"><span style="font-size: small;"> <span style="mso-ansi-language: EN-GB;" lang="EN-GB">Gross cracking of die-casting dies with inferior toughness sometimes occurs through too low preheating temperature and/or too slow cooling during quenching. This study aimed to clarify the influence of cooling rate on the toughness of the hot-work tool steel grade Uddeholm Vidar Superior at ambient temperature and at 200 °C, a typical preheating temperature for aluminium die-casting dies. Toughness was measured through instrumented Charpy V-notch impact testing. </span><span style="mso-ansi-language: EN-GB;" lang="EN-GB">The decrease in energy absorption with increasing cooling time between 800°C and 500°C both at both ambient temperature and 200 °C was pronounced. At ambient temperature, the decrease in total energy was a consequence of a decrease in initiation energy whereas, at 200 °C, the decrease in total energy was due to a decrease in propagation energy. </span><span style="font-size: small;"> </span></span></span></span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-size: small;"> </span></div><span style="font-family: Times New Roman; font-size: small;"> </span>