SAE J1692:2017 pdf free
SAE J1692:2017 pdf free.Valve Seat Insert Information Report
The flexible or skirted insert shown in Figure 3 is used in some air-cooled engine applications.The clearance between the flange diameter and the cylinder head allows slight movement of the cylinder head to occur without distorting the seating surface. Insert retention is accomplished by an interference fit between the skirt diameter and the head. This puts the insert head interface farther away from the port in a relatively cooler area, thus aiding retention. Insert retention is also aided by a nominal 1/4 degree reverse taper on the skirt outside diameter.
Valve seat inserts are manufactured using cast, wrought, or sintered powder metallurgy processes.Wear resistance is generally related to the volume fraction of hard phases such as martensite, carbides, nitrides, and oxides. The major alloy categories in each of these three groups follows along with a brief metallurgical description of each category.
Low alloy grey iron is used for light- to moderate-duty intake applications and light- duty exhaust applications. It is sometimes used in the as-cast condition, but may also be heat treated for improved strength and hardness. Grey iron offers low alloy cost and good machinability. For certain applications, it is also less abrasive to the mating valve.
Ductile iron finds limited use in high performance applications seating against titanium valves. It is usually supplied in the hardened and tempered condition.
White iron is employed primarily in heavy-duty intake applications for wear resistance.White irons used for inserts normally have significant additions of carbide formers such as chromium, tungsten, vanadium, or molybdenum. They are also normally heat treated so that the final microstructure consists of alloy carbides in a martensitic matrix.
Austenitic Cast lron Alloys- -UNS1 (Ni-resistTM) is a typical example of these alloys and is used in some aluminum head applications. It is a highly alloyed austenitic iron which possesses a high coefficient of thermal expansion.SAE J1692 pdf free download.
