MFN had the pleasure to talk to Keynes Khu, Marketing Director of Yanchen Saipu Metal Product Co., Ltd.

(?) MFN: Can you please make a brief introduction concerning abrasives?

(!) K. K.: There are two types of abrasives; metallic and non-metallic. The metallic abrasives are divided into cast shot and cut wire shot, while the non-metallic are either glass beads or ceramic beads.

The purpose of shot peening is completely different to blast cleaning. Blast cleaning is only a surface preparation which does not change the mechanical properties of the material. In shot peening the goal is to bring the right residual tensile stress into the surface to improve its resistance against failures and to increase the life of the parts. (Fig. 1)

(?) MFN: How to choose the right type of abrasives?

(!) K. K.: That depends on many different factors such as specification requirements, requested intensity and surface roughness. According to this information, the size, hardness, material and shape of the abrasives has to be chosen.

The size is normally selected based on the surface condition and the roughness requirements. Sometimes double-peening is requested to get the right residual tensile stress and surface roughness.

The hardness is determined by the specified residual tensile stress and the hardness of the parts. The shot is usually a bit harder than the surface (HRC3).

(?) MFN: What is the difference for these kinds of abrasives?

(!) K. K.: The different characteristics of these abrasives are:

Cast Steel Shot:
• Shot can fail due to fracture
• Typical defects: hollows, doubles, wrong shape
• Early impacts will remove most of the defective (weak) shot                                      

Cut Wire Shot (Conditioned):
• Cut wire must be conditioned before use
• Roundness continues to improve with use
• Final shape is spherical
• Durability 3-4 times longer compared with cast shot
• Cost 2-3 times higher than cast shot

Ceramic Beads:
• Basically dust-free
• Expensive
• Suitable for low intensities (lower 'A' or 'N' scale)
• Requires conditioning to remove attached satellites

Glass Beads:
• Very round
• Only used for very low intensities ('N' scale)
• Does not leave ferrous contamination
• Broken pieces may be embedded into the part

(?) MFN: How does your company serve the customer on shot peening?

(!) K. K.:  Our company "Yanchen Saipu Metal Product Co.,Ltd" is a manufacturer of all kinds of cut wire shot abrasives, both used for shot peening and shot blasting. We provide a one-stop station service to our customers for shot peening and shot blasting. We are able to advise customers how to choose the best possible shot abrasives. Furthermore, we also provide peening accessories to customers such as: Almen strips, Almen gages, PeenScan Pens, etc.

MFN would like to thank Keynes Khu for this interview!

For Information:
Saipu Metal Product Co.,Ltd
A-13 Minhao  Industrial Park
224300 Yancheng Jiangsu P.R.C
Tel. +86.515.6986-9677
E-mail: nabrasive@vip.163.com
www.superiorcutwireshot.com