Berk Korucu - 030080104 - 8th Week Definitions

1) Babbitting (About Coating) (Surface Treatment)


Previous Definition


--Babbitting consists of attaching a layer of softer metal (usually a tin-lead composition) to a part of much sturdier composition which acts as a supporting element. The soft layer, or the babbitt, has excellent antifrictional properties. In shafts, the babbitt averts galling and scoring of the surface, while the inner, stiff core acts as its support in torsion, when rotating.
--Babbitting is used with bearing shells, hardware elements, automotive connecting rods, jewelry, and numerous other applications. The babbitt is attached to the supporting metal by either of two methods:
• Mechanical bonding of babbitting is performed by using fasteners, dovetails, and other grooves.
• Heating of the babbitting material along with its supporting part and allowing the assembly to first cool at the area of contact between the babbitt and its support. This method is useful with shells, where the babbitt is introduced in the form of a mandrel.

(Ivana Suchy, Handbook of die design , page 678)


New Definition (Better)


Babbitt, also called Babbitt metal or bearing metal, is an alloy used for the bearing surface in a plain bearing. The original Babbitt metal was invented in 1839 by Isaac Babbitt  in Taunton, Massachusetts, USA. To deemphasize the term's eponymous character, modern writers sometimes lowercase it (Babbitt). It is preferred over the term "white metal," which also refers to bearing metal, because "white metal" has other meanings.Babbitt metal is most 
commonly used as a thin surface layer in a complex, multimetal structure, but its original use was as a cast-in-place bulk bearing material. Babbitt metal is characterized by its resistance to galling. Babbitt metal is soft and easily damaged, which suggests that it might be unsuitable for a bearing surface. However, its structure is made up of small hard crystals dispersed in a softer metal, which makes it a metal matrix composite. As the bearing be worn, the softer metal 
erodes somewhat, which creates paths for lubricant between the hard high spots that provide the actual bearing surface. When tin is used as the softer metal, friction causes the tin to 
melt and function as a lubricant, which protects the bearing from wear when other lubricants are absent. Thermal spraying techniques are coating processes in which melted materials 
are sprayed onto a surface. The "feedstock" is heated by electrical (plasma or arc) or combustion flame. Coating quality is usually assessed by measuring its porosity, oxide 
content, macro and micro-hardness, bond strength and surface roughness. Generally, the coating quality increases with increasing particle velocities.
Several variations of thermal spraying are distinguished: 


• Cold spraying 
• Detonation spraying 
• Flame spraying(wire and arc) 
• High-velocity oxy-fuel coating spraying (HVOF) 
• Plasma spraying 
• Warm spraying 
• Wire arc spraying
(M. Azizpour, S.Norouzi, H. Majd, Babbitt Casting and Babbitt Spraying Processes, p.1034)




2) Thermodiffusion Process (Surface Treatment)


Previos Definition (Better)

Coatings produced by thermodiffusion are formed at high temperatures and in controlled atmospheres of specific content. Diffusing materials of gaseous, solid (powder), or molten form are placed in contact with the part to be coated and allowed to enter its surface. The coated material, usually steel or iron, forms an alloy with the diffusing components within the upper layers of the coated surface. The coating emerges uniform in thickness throughout the part.

The temperature of the process is somewhere near the melting point of the diffused metal and the heating procedure is conducted in an oven. Various processes use different temperature settings: These are either below or above the melting point preferences, according to the diffusion substance used. The temperature of the process influences not only the speed of the coating operation, but also the character and texture of the finish as well.

The most common thermodiffusion processes are cementing and nitriding, but other applications utilizing chromium, aluminum, sulfur, and zinc are being widely used. With zinc, the process is called sheradizing, and the metal material is added in the form of powder. With the melting point of zinc at 786°F, sheradizing is usually performed at temperatures ranging from 600 to 700°F. Thermodiffusing of sulfur is performed along with nitrogen, and the process is almost the same as that of nitriding.

Newer diffusing processes, utilizing boron and silicon, were developed for attainment of an extra high surface hardness, abrasion and wear resistance, and resistance to high temperatures. Another new technique involves a combination of the thermodiffusion process with electrolysis of the salt melt.

Thermodiffusion is preferred as the surface treatment of small parts, since a distortion of products and their dimensional alterations may occur with larger objects. A considerable variation in wall thickness or sharp corners on the part will magnify these complications.

(Ivana Suchy, Handbook of Die Design, McGraw Hill Pub., 2006, Second Edition, p.675-676)

New Definition

The thermal diffusion (TD) process, which is also referred to as the thermoreactive deposition/diffusion (TRD) process and the Toyota diffusion process, is a high-temperature surface modification process that forms a hard, thin, wear-resistant layer of carbides, nitrides, or carbonitrides on steels as well as other carbon-containing materials such as nickel and cobalt alloys, cemented carbides, and steelbonded carbides (TiC dispersed in a steel matrix). In the TD process, the carbon and nitrogen in the steel substrate diffuse into a deposited layer with a carbide-forming element such as vanadium, niobium, tantalum, chromium, molybdenum, or tungsten. The diffused carbon or nitrogen reacts with the carbide- and nitride-forming elements in the deposited coating so as to form a nonporous, metallurgically bonded coating at the substrate surface.

(J.R. Davis, Thermal Diffusion Process, p.1)

3) Nedox (in Magnaplate) (Coating)

Previous Definition

Coating Description: Controlled infusion of various proprietary polymers within a modified nickel alloy plating. Subsequent controlled treatment cycles assure thorough infusion of the proprietary polymer material into the surface layer and concurrently increase hardness of the matrix. Meets and exceeds requirements of MIL-C-26074, Class 1, 2, 3 and 4, and its replacement specs AMS 2404 and 2405. Applications: Steel, stainless, copper, brass, bronze, titanium, and aluminum are the basic metals that can be enhanced by the use of one of 13 types of NEDOX. Abrasion resistance, lubricity, corrosion resistance and/or mold release can be obtained through the use of NEDOX.
(General Magnaplate Corp., Engineering Date and Application Guide)

New Definition (Better)

The production of synergistic coatings on steel (Nedox) or aluminum (Tufram) is based on the

principle of infusion of a dry lubricant or polymer into the coatings. General Magnaplate has developed a family of such coatings (Nedox), each one representing specific properties, such as hardness, lubricity, corrosion protection, and dielectric strength. The standard hardfacing for steel is an electroless nickel coating. There are a number of electroless nickels that vary the phosphorus content and consequently have differences in hardness and corrosion resistance. Choice of such a coating varies and is based on the application requirements.

Synergistic coatings for aluminum (Tufram) have been used successfully for many years. The system can accommodate almost all aluminum alloys, provided a copper content of 5% and a silicon content of 7% are not exceeded. Higher percentages of these constituents (set up too great a change in substrate resistivity, hence) prevent the buildup of required film thickness.

The prime purpose of the Tufram system is to produce films having properties such as improved wear resistance, better surface release (lower coefficient of friction), good corrosion resistance, and high dielectric strength.

The principle of these coatings is based on a hardcoat after which a polymer or dry lubricant is infused into the coating substrate.

All coatings are used in a wide variety of industries. Some are in compliance with the regulations of the U.S. Food and Drug Administration and can be used in food and medical applications.The improvement in wear resistance to aluminum ranges from 5 to 25 times that without the coatings. It is difficult to put an exact number on the improvement, since it varies from one application to another. 

Synergistic coatings are not really “coatings” in the conventional sense of the word. They are created during multistep processes that combine the advantages of anodizing or hardcoat plating with the controlled infusion of low friction polymer and/or dry lubricants. These “coatings” become an integral part of the top layers of the base metal rather than merely a surface cover. Since the resulting surfaces are superior in performance both to the base metal and to the individual components of the coatings,

the proprietary processes that produce them are identified as “synergistic.

(A. Tracton, 

Coatings Technology 

Fundamentals, Testing, 

And Processing Techniques, p

.34-1 - 34-2)




4) Plasmadize (in Magnaplate) (Coating)


Previous Definition (Better)


Coating Description: This next generation of thermal spray coatings features high levels of wear and corrosion resistance, dry-lubricity and mold release not possible with conventional spray methods. Infused matrix of metals, ceramics, proprietary polymers and/or dry lubricants creates structural integrity and a non-porous, moisture-proof surface. Applications: PLASMADIZE is ideal for protecting or restoring all types of metal parts. Available as a release (non-stick) or gripping surface up to +1300°F (+704°C). Ideal for a wide range of food and pharmaceutical industry applications.
(General Magnaplate Corp., Engineering Date and Application Guide)


New Definition




Several trademarked General Magnaplate coating products will likely find application with Custom Moldmaking Process Technolog (CMPT) tools. Plasmadize provides a permanent release coating that can eliminate expensive and in some cases toxic sprayed or wiped on release agents, as well as adds to the durability of the tool face. Further, the chemistry of Plasmadize allows for synergistic impregnation of a customer’s choice of constituents — from ceramics to tungsten carbide to a combination that optimizes the best properties of each element (such as a wear resistant area surrounded by permanent release). This coating can also provide an effective sealant for pulling vacuum on composite parts, as well as a permanent release coating.
(E. V. Aversenti, Robotically Applied CMPT, p.3)






5) Standard (Conventional) Mills (in Roll Forming) (Material)


Previous Definition (Better)

The shafts of the standard (conventional) mills are supported at both ends. This design enables building and use of the mills for materials with any width and thickness. Therefore, standard mills are the most popular machines used to roll form metals. In most cases, the drive-side (inboard) stand holds the shafts in position and accommodates the drive. The operator-side (outboard) stand supports the other end of the shafts. This stand is removable to facilitate roll changes. Both the operator- and drive-side stands are fastened to a common base. The drive-side stands are fixed at one location. The operator-side stands are in most mills also fixed at one position. In other types of mills, the operator-side stands can be placed into different locations along the shafts to accommodate wider and thinner material, or narrower but thicker material.

( Roll Forming Handbook,George T. Halmos; Page: 2-9)

New Definition 

Saucon's standard mills are represented by 28, 18 adn 12-in mills. The 28 and 18-in mills are each composed of a 3-high roughing stand, a 3-hig intermediate and a 2-high finishing stand. Figure 12 shows the arrangement of the 18-in mill. The 12-in mill is composed of ten stands, each 2-high, the first six stands of which are arranged in a semi-continuous direction with the remaining four stands arranged cross-country style, see Figure 13. The 28-in mill is steam driven and the 18 and 12-in mills are electrically driven. Straightening of the finished product from theese mills is accomplished by rotary straighteners for each individual mill.

The usual number of passes taken on the 28 and 18-in mills is five in the roughing, three in the intermediate and one in the finishing stand, see Figure 14, 15 and 16. The roughing stand may sometimes require three or four passes, depending on the size of the section; and also, depending on the particular gage rolled, only one pass may be necessary in the intermediate stand.

The 28-in mill (Figure 17) is preceded by a 32-in. 2-high, reversing breakdown mill which is electrically driven, see Figure 18. This mill, in addition to supplying shaped blooms or rectangular blooms for the 28-in mill, also supplies blooms and billets for the 18 and 12-in mills. The entire production of the 32-in mill is related before rolling to the finish product on the standard mills.

(R. E. Shaffer, Rolling of Structural Steel, p.104-105)