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.

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.

The low-pressure heat treatment of metals enables the continuous improvement of the mechanical and plastic properties of products, such as hardness, abrasion resistance, etc. A significant problem related to the operation of vacuum furnaces for heat treatment is that they become unsealed during operation, resulting from the degradation of seals or the thermal expansion of the construction materials. Therefore, research was undertaken to develop a prediction model for detecting leaks in vacuum furnaces, the use of which will reduce the risk of degradation in the charge being processed. Unique experimental studies were carried out to detect leakages in a vacuum pit furnace, simulated using the ENV 116 reference slot. As a consequence, a prediction model for the detection of leaks in vacuum furnaces- which are used in the heat treatment of metals- was designed, using an artificial neural network. (93% for MLP 15-10-1) was developed. The model was implemented in a predictive maintenance system, in a real production company, as an element in the monitoring of the operation of vacuum furnaces.