Design And Construction Of A Forge Hearth Equipment For Heat Treatment Of Metals

ABSTRACT

In the early days, it was common for a blacksmith’s apprentice to use their lungs to blow air into a hollow tube, directly into the base of the fire. This method was not very effective as the majority of the oxygen they inhaled would get absorbed by the lungs, and the exhalation contained a lot of carbon dioxide which did not help the fire. Not only that – heavy breathing would quickly make apprentices dizzy from hyperventilation and could result in them passing out. Many apprentices would have begun their training before the age of ten. Life was tough for a blacksmith apprentice in those days, for sure. This was not an effective method. It was this reason that forge blower was introduced. The blower was designed to convert driver energy to kinetic energy by accelerating it to the outer rim of the impeller and the impeller driven by the connecting shaft adds the velocity component to the air by centrifugally casting the air away from the impeller vane tips.

CHAPTER ONE

1.1                                                        INTRODUCTION

Heat Treating is used to alter and improve the physical properties of a given material.  Typical heat treatment techniques applied to steel forgings include annealing, normalizing, quenching, and tempering.  Precipitation hardening applies to superalloys, titanium and some PH stainless steels  Annealing.

This device is a type of hearth used for heating metals in the furnace, or the workplace (smithy) where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature where it becomes easier to shape by forging, or to the point where work hardening no longer occurs. The metal (known as the “workpiece”) is transported to and from the forge using tongs, which are also used to hold the workpiece on the smithy’s anvil while the smith works it with a hammer. Sometimes such as when hardening steel or cooling the work so that it may be handled with bare hands; the workpiece is transported to the slack tub, which rapidly cools the workpiece in a large body of water.

This forge hearth comprises of electric blower and manual operated to delivers consistent air supply to the base of the fire to aid the combustion process of a furnace. Supplying the fire with oxygen means that the fire can get to a temperature hot enough to manipulate and craft iron.

Supplying air manually will reduce productivity and more man hour to accomplish a given task.  Thus, an electric blower was designed in this regard with an efficient electric motor as the driver. The suction conditions and other application data are appropriately used to calculate the design parameters such as: suction specific speed, the power input to the blower, the inlet and outlet velocity, the twisting moment of the impeller shaft etc.

• BACKGROUND OF THE PROJECT

A forge blower is a device designed to create air flow toward a fire in a coal forge or other type of forge system. This device replaces the hand-operated bellows a blacksmith would traditionally use to stoke the fires to keep the temperature high enough for metal working. A modern forge blower will be electrically operated to ensure consistent air delivery and a more powerful stream of oxygen reaching the fires and the coals being heated. The air will usually be directed through a pipe known as a tuyere to ensure proper delivery to the fire.

In the past, an assistant was needed to operate a bellows, which was a type of air blower that was operated by hand. This person was responsible for stoking the fire before and during the metalworking process, for which the blacksmith was responsible. The assistant would need to be able to stay out of the blacksmith’s way, but also be ready to keep the fires appropriately hot when necessary. This could make for a crowded work space, and injuries were possible as a result. Today, the forge blower is mounted out of the way and it eliminates the need for an assistant to operate the air flow machine.

The size of the forge blower can vary according to the size of the fire pot and hearth. In many cases, the forge blower is quite large because it must house both a motor and other components that create the flow of air. Once the fan within the forge blower creates an airflow, the air is forced through a tube that redirects it toward the fire pot above. The coals within the fire pot are then stoked to the appropriate temperature and maintained at that temperature to ensure a better metalworking environment.

Before electric blowers became common, some were operated by a hand crank. This type of forge bellow was the technology that essentially replaced hand bellows that were pumped; this unit was instead outfitted with a hand crank mounted to the side of the bellow body. An assistant was still usually necessary to operate this machine, but the air blower could be mounted away from the fire pot and hence away from the blacksmith working the metal. The assistant would stand away from the hearth and turn the hand crank vigorously to produce an airflow that could be redirected through a pipe to the fire pot.

1.2                                             OBJECTIVE OF THE PROJECT

The objective of the project is to fabricate an electrical and hand operated used to produce consistent air supply to the base of the fire to aid the combustion process.

1.3                                              PURPOSE OF THE PROJECT

The main purpose of this work is to build  a device designed to create air flow toward a fire in a coal forge or other type of forge system such as furnace.

1.4                                         SIGNIFICANCE OF THE PROJECT

The forge blower is one of the most important and portable tools in a blacksmith’s workshop. The function of the blower is to deliver a consistent air supply to the base of the fire to aid the combustion process. Supplying the fire with oxygen means that the fire can get to a temperature hot enough to manipulate and craft iron objects – without a consistent supply of oxygen, this task is nearly impossible. The added benefit of device is that it is very quiet, compact, robust and reliable.

1.5                               APPLICATION OF MOBILE FORGE BLOWER

This work is used for local and industrial use for shaping or bending of metal. Forge blower is one of the most important and portable tools in a blacksmith’s workshop.

1.6                                                 SCOPE OF THE PROJECT

This device is operated electrically when there is power supply and manually when is power outage. The blower was designed to convert driver energy to kinetic energy by accelerating it to the outer rim of the impeller and the impeller driven by the connecting shaft adds the velocity component to the air by centrifugally casting the air away from the impeller vane tips.

Parts produced by forging are stronger than casted or machined parts. During the forging process the internal grain of the part changes its form and continuous forging for a few minutes strengthens the part’s characteristics.

Fans for forges where the diameter of the air feed pipe is very narrow (i.e. between 40 to 60mm) was used. Because a smaller feed pipe means a greater resistance to air flow, more pressure is required to push the air through the pip and into the heath of the fire. Extra velocity may also be required depending on the length and shape of the feed pipe, or the type of blacksmithing being undertaken.

1.7                                           LIMITATION OF THE PROJECT

• When operating manually, Forge blower prevents work hardening and hence increases the difficulty of performing other machining operations on the part.
• Producing forged parts involves a lot of expenditure for the machinery, dies, tools and personnel.
• Some forging requires metal-forming dies, which are required to be precisely machined and heated to properly shape the piece. This is not always achievable by novices or not very-high experienced engineers.
• It is very expensive to produce compared to traditional means of blowing air.

1.8                                     PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to this study. In this chapter, the background, significance, objective limitation and problem of this study were discussed.

Chapter two is on literature review of the study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.