The right selection of carburizing gas flow rates in the low-pressure carburization process is a key factor in terms of its efficiency. However, a correct calculation of the amount of carburizing gas required for uniform carburization of parts, taking into account the process temperature and batch size, is still problematic. For this reason, modern carburizing processes are carried out using an excessive belaying flow of carburizing gases. In this work steel parts (16MnCr5) were carburized in a variable-flow carburizing process (960 °C) individually matched to each segment of saturation. The effect of the variable-flow on the microstructure, surface hardness, and case hardness depth was evaluated and compared to that of a control group. It was proven that the amount of the mixture used in the variable-flow carburizing process can be significantly reduced to 54% of that consumed during the regular constant-flow carburizing without affecting the properties of the hardened layer of the steel parts.
KurzfassungTraditionally, case hardening is based on carburizing in atmospheres and oil quenching; this is carried out in sealed quench furnaces and in continuous lines (pusher, roller or rotary furnaces). ey are technologies and devices developed more than 50 years ago and, over the course of time, they have exhausted their development potential. At present, they hardly meet the incoming requirements of the modern industry regarding quality and replicability, integration and organization of production, and environment protection.A solution for weak points of traditional case hardening is the use of vacuum technologies and equipment. Vacuum carburizing increases the resulting precision and replicability, and the variety of vacuum equipment for heat treatment allows the adaptation to modern industry requirements. Two applications are described in the article. e rst one -evolutionary -is based on the triple-chamber vacuum furnace for semi-continuous production as a wide alternative for traditional devices. e second system -innovative -is based on the true single-piece ow method. Both solutions have specific and characteristic properties that predispose them for different applications depending on quality requirements and organization of production. n
Pyrowear ® Alloy 53 steel is an excellent material for the construction of drive transmission components (gears, shafts, etc.) which have to operate in difficult conditions primarily in the aviation industry (Fig. 1.). Among the properties of such items is a high case hardness and abrasion-resistance, while the core remains flexible and is capable of carrying large impact loads. They can work at elevated temperatures with limited lubrication. The thermal treatment of such materials is based on case hardening by means of carburizing. This paper presents the technology of vacuum carburizing of Pyrowear ® Alloy 53 steel. It discusses the methods of establishing different profiles of carbon concentration in a layer and their influence on the hardness profile. The effects of sub-zero treatment and tempering on the properties of the hardened case are also considered. It also presents a SimVaC® simulator of vacuum carburizing, designed especially for Pyrowear ® Alloy 53 steel, which provides highly accurate predictions of the outcome of the process as the profile of carbon concentration in the layer, or vice versa: establishes the process parameters which will guarantee the required profile.
Material distortion is an undesired characteristic observed when a produced component requires a thermo-chemical heat treatment process followed by a rapid quench to obtain desired mechanical and metallurgical properties with uniform case depth and hardness profile. Due to the distortion taking place during this process, the manufacturer is faced with the costly choice of leaving excess material on a machined component before the heat treatment process, only to be removed after the heat treatment process by post heat treatment manufacturing methods. When steps are taken to reduce material distortion (prior to hard machining operations), manufacturers can significantly reduce costs and subsequently speed up the overall manufacturing process. This paper will discuss the unique method of distortion control for heat treated and quenched components by use of a 4-Dimensional High-Pressure Gas Quench (4D Quench®) technique. This system has the ability to quench a single component without fixturing versus either a free quench or complex press quench approach. The 4D Quench® process results in components being individually quenched in an identical manner while having minimal distortion in relation to the green component. 4D Quench® systems are easily integrated into machining centers improving lead time and costs associated with traditional heat treatment processes.
Purpose: Purpose of this paper is development of single-piece flow system to precision thermal treatment of parts of mechanical gear using a short-pulse low-pressure carburising technology (developed for a new large-chamber furnace). Design/methodology/approach: Sections of the article discuss the novel constructions of the device in which parts being carburised flow in a stream, as well as the low-pressure carburising experiment. Findings: The method has been found proper carburised layers on typical gear used in automotive industry. Research limitations/implications: The short-pulse low-pressure carburising technology needs further investigation to fully understand its all mechanisms. Practical implications: The device resulting from the experiment can be a fully robotised part of a production line which can be included in a system of automatic control of a production process. Originality/value: The device resulting from the experiment is only known solution on the world.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.