Biocompatibility and Corrosion Response of Laser Joined NiTi to Stainless Steel Wires

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Grant Brandal ◽  
Y. Lawrence Yao ◽  
Syed Naveed
Keyword(s):  
Stainless Steel ◽  
Implantable Medical Devices ◽  
Laser Joining ◽  
Steel Wires ◽  
Nickel Release ◽  
Microbiological Testing ◽  
Good Biocompatibility ◽  
Nickel Release Rate ◽  
Niti Wires ◽  
Joining Process

The biocompatibility of nickel titanium (NiTi) wires joined to stainless steel (SS) wires via laser autogenous brazing has been evaluated. The laser joining process is designed to limit the amount of mixing of the materials, thus preventing the formation of brittle intermetallic phases. This process has the potential for manufacturing implantable medical devices; therefore, the biocompatibility must be determined. Laser joined samples underwent nickel release rate, polarization, hemolysis, and cytotoxicity testing. Competing effects regarding grain refinement and galvanic effects were found to influence the corrosion response. After 15 days of exposure to a simulated body fluid, the total nickel released is less than 2 ug/cm2. Numerical modeling of the corrosion currents along the wires, by making use of polarization data, helped to explain these results. Microbiological testing found a maximum hemolytic index of 1.8, while cytotoxicity tests found a zero toxicity grade. All of these results indicate that the autogenous laser brazing process results in joints with good biocompatibility.

Beneficial Interface Geometry for Laser Joining of NiTi to Stainless Steel Wires

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Grant Brandal ◽  
Gen Satoh ◽  
Y. Lawrence Yao ◽  
Syed Naveed
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Stress Component ◽  
Processing Parameters ◽  
Shear Stress Component ◽  
Laser Joining ◽  
Steel Wires ◽  
Metal Pair ◽  
Cone Apex ◽  
Interface Geometry

Joining the dissimilar metal pair of NiTi to stainless steel is of great interest for implantable medical applications. Formation of brittle intermetallic phases requires that the joining processes used for this dissimilar pair limits the amount of over-melting and mixing along the interface. Thus, because of its ability to precisely control heat input, laser joining is a preferred method. This study explores a method of using a cup and cone interfacial geometry, with no filler material, to increase the tensile strength of the joint. Not only does the cup and cone geometry increase the surface area of the interface, but it also introduces a shear stress component, which is shown to be beneficial to tensile strength of the wire as well. The fracture strength for various cone apex angles and laser powers is determined. Compositional profiles of the interfaces are analyzed. A numerical model is used for explanation of the processing parameters.

Nickel Release Rate of Type 303 Free Cutting Austenitic Stainless Steel

2015 ◽  
Vol 1096 ◽  
pp. 114-119
Author(s):  
Jun Ping Yuan ◽  
De Dong Chen ◽  
Hai Rui Bo
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Release Rate ◽  
Manganese Sulfide ◽  
Contrast Material ◽  
304 Stainless Steel ◽  
Test Material ◽  
Nickel Release ◽  
Prolonged Contact ◽  
Nickel Release Rate

Type 303 austenitic stainless steel has been applied in jewelry production, and its nickel release rate has become a concerned issue in the jewelry industry. In this paper, the commercial type 303 stainless steel was used as the test material, while 304 stainless steel as the contrast material; their nickel release rates and corrosion behaviors in artificial sweat were studied. The results show that the actually measured nickel release rate of 303 stainless steel reaches 2.06μg/cm2/week, nearly 25 times higher than that of 304 stainless steel, which exceeds the threshold specified in nickel release standard EN1811:2011 for jewelries coming into direct and prolonged contact with the skin (0.88μg/cm2/week), and its adjusted value also exceeds the threshold specified in Nickel Directive 2004/96/EC for puncture accessories (0.35μg/cm2/week). The high nickel release rate for 303 stainless steel is mainly caused by its high sulfur content and the inevitable formation of manganese sulfide inclusions, which will cause the pitting and exacerbate the material corrosion. Considering the risk of nickel sensitization of 303 stainless steel, it is not suggested to use 303 stainless steel as the jewelry material, especially for piercing jewelry.

Laser Direct Joining Between Stainless Steel and Amorphous Polyamide Plastic

2011 ◽  
Author(s):  
Yousuke Kawahito ◽  
Seiji Katayama ◽  
Koji Nishimoto
Keyword(s):  
Stainless Steel ◽  
Shear Strength ◽  
Dissimilar Materials ◽  
Dissimilar Material ◽  
Si3n4 Ceramic ◽  
Laser Joining ◽  
Engineering Plastic ◽  
Joining Process

Joining of the dissimilar materials is necessary and important from a manufacturing viewpoint. Therefore, the authors have developed a new laser direct joining method between metals and plastics. In this research, such joining was applied to join Si3N4 ceramic and PET engineering plastic, although the metal was replaced by the ceramic. The shear strength of the joints was 3100 N, which was strong enough to elongate PET plates of 2 mm thickness and 30 mm width. It was confirmed that this laser joining process was effective to directly produce a strong dissimilar material joint of a ceramic and an engineering plastic.

scholarly journals Effects of Interfacial Geometry on Laser Joining of Dissimilar NiTi to Stainless Steel Wires

2013 ◽  
Author(s):  
Grant B. Brandal ◽  
Gen Satoh ◽  
Y. Lawrence Yao ◽  
Syed Naveed
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Biomedical Applications ◽  
Intermetallic Phases ◽  
Dissimilar Metal ◽  
Laser Joining ◽  
Steel Wires ◽  
Shear Component ◽  
Metal Pair ◽  
Cone Apex

Joining of the dissimilar metal pair NiTi to stainless steel is of great interest for implantable biomedical applications. Formation of brittle intermetallic phases requires that the joining processes limit the amount of over-melting and mixing along the interface. Thus, laser joining is a preferred method due to its ability to precisely control heat input. This study explores a method of using a cup and cone interfacial geometry, with no filler material, to increase the tensile strength of the joint. Not only does the cup and cone geometry increase the surface area of the interface, but it also introduces a shear component, which is shown to be beneficial to tensile strength of the wire as well. The fracture strength for various cone apex angles and laser powers is determined. Compositional profiles of the interfaces are analyzed. A numerical model is used for explanation of the processing.

BRILLIANT 2101 T-1 AP

Alloy Digest ◽  
2012 ◽  
Vol 61 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Tensile Properties ◽  
Stainless Steels ◽  
Duplex Stainless Steels ◽  
Good Balance ◽  
Steel Wires

Abstract Stoody AP stainless steel wires are all-position wires. The nickel in this product will achieve a good balance of austenite and ferrite in lean duplex stainless steels. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on forming and joining. Filing Code: SS-1118. Producer or source: Stoody Company.

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process

2021 ◽  
pp. 088532822110195
Author(s):  
Moataz Elsisy ◽  
Mahdis Shayan ◽  
Yanfei Chen ◽  
Bryan W Tillman ◽  
Catherine Go ◽  
...  
Keyword(s):  
Laser Power ◽  
In Vitro Study ◽  
Spot Size ◽  
Laser Joining ◽  
Study Results ◽  
Energy Laser ◽  
Joining Process ◽  
Endovascular Devices ◽  
Low Energy Laser

Nitinol is an excellent candidate material for developing various self-expanding endovascular devices due to its unique properties such as superelasticity, biocompatibility and shape memory effect. A low-energy laser joining technique suggests a high potential to create various large diameter Nitinol endovascular devices that contain complex geometries. The primary purpose of the study is to investigate the effects of laser joining process parameters with regard to the mechanical and biocompatible performance of Nitinol stents. Both the chemical composition and the microstructure of the laser-welded joints were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In vitro study results on cytotoxicity demonstrated that the joining condition of 8 Hz frequency and 1 kW laser power showed the highest degree of endothelial cell viability after thermal annealing in 500°C for 30 min. Also, in vitro study results showed the highest oxygen content at 0.9 kW laser power, 8 Hz frequency, and 0.3 mm spot size after the thermal annealing. Mechanical performance test results showed that the optimal condition for the highest disconnecting force was found at 1 Hz frequency and 1 kW power with 0.6 mm spot size. Two new endovascular devices have been fabricated using the optimized laser joining parameters, which have demonstrated successful device delivery and retrieval, as well as acute biocompatibility.

Bending Properties of General Purpose Stainless Steel Wire Formed for Orthodontic Use

2013 ◽  
Vol 746 ◽  
pp. 394-399
Author(s):  
Niwat Anuwongnukroh ◽  
Yosdhorn Chuankrerkkul ◽  
Surachai Dechkunakorn ◽  
Pornkiat Churnjitapirom ◽  
Theeralaksna Suddhasthira
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Orthodontic Treatment ◽  
Steel Wire ◽  
General Purpose ◽  
Stainless Steel Wire ◽  
Bending Test ◽  
Bending Properties ◽  
Steel Wires ◽  
Significant Difference

The archwire is generally used in fixed appliances for orthodontic treatment to correct dental malocclusion. However, it is interesting to know whether general purpose stainless steel wire could replace commercial orthodontic archwire in orthodontic practice for economic reasons. The purpose of this study was to determine the bending properties of general purpose stainless steel wire compared with commercial orthodontic stainless steel wires after forming as an archwire for orthodontic use. The samples used in this study were 90 general purpose and 45 commercial (Highland) round stainless steel wires in 0.016, 0.018, and 0.020 sizes (30 general purpose and 15 commercial wires for each size). All 15 general purpose stainless steel wires with different sizes were formed into orthodontic archwire with a Universal Testing Machine. All samples were tested (three-point bending test) for mechanical properties. The results showed no significant difference between general purpose and commercial orthodontic wires in size 0.016 for 0.1 mm offset bending force, 0.2% yield strength, and springback. Although many mechanical properties of general purpose wires differed from commercial wires, their values conformed to other previous studies within the range of clinical acceptance. In conclusion, orthodontic formed general purpose round stainless steel wires had statistically different (p <0.05) mechanical properties from commercial orthodontic stainless steel wires (Highland) but the mechanical properties were acceptable to use in orthodontic treatment.

Flexure Modulus of Orthodontic Stainless Steel Wires

1981 ◽  
Vol 60 (2) ◽  
pp. 139-145 ◽  
Author(s):  
D.K. Yoshikawa ◽  
C.J. Burstone ◽  
A.J. Goldberg ◽  
J. Morton
Keyword(s):  
Stainless Steel ◽  
Steel Wires

Evaluation of the Tube to Tubesheet Joining Process in an AL6XN® Feedwater Heater

2017 ◽  
Author(s):  
Eric Svensson ◽  
Michael Catapano
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Cooling Water ◽  
Intimate Contact ◽  
Pull Out ◽  
Digital Microscope ◽  
304 Austenitic Stainless Steel ◽  
Type 304 ◽  
Tube Expansion ◽  
Joining Process

Type 304 austenitic stainless steel is the most common tube material utilized for nuclear feedwater heaters, however, some utilities have experienced problems with Stress Corrosion Cracking (SCC), especially when they utilize brackish cooling water and have experienced condenser tube leaks. This has forced some utilities to explore other options when it comes to high pressure feedwater heaters (HP FWH) tubing materials. AL6XN® is considered a “super” stainless steel that is resistant to (SCC), however, it is not immune (AL6XN is a trademark of ATI Technologies). Based on the relative inexperience and unknowns related to the use of AL6XN tubing in high pressure, nuclear feedwater heater applications, a detailed mock-up procedure was outlined as part of the replacement heater specification which would allow the evaluation of the tube to tubesheet joining processes. Since AL6XN can still be affected by SCC; steps were taken in order to minimize the imposed stress levels and any potential for the inadvertent inclusion of contaminants during the fabrication steps at the tube mill and at the feedwater heater Manufacturer’s shop. The desire to minimize stresses also applies at the tube to tubesheet joint, therefore, it was desired not to stress the tube more than absolutely necessary in achieving a reliable, leak tight joint. The mock-up details and procedures were therefore generated with these objectives in mind, so as to give consideration for the ability to check different configurations in order to determine the most efficient tube to tubesheet joining process. Several tubes in the mock-up were subjected to a pull out test in order to quantify the joint strength in the different configurations. The mockup was then sectioned and inspected under a digital microscope to verify intimate contact between the tube and the tubesheet. Once the optimal procedure was identified, four identical HP FWHs were constructed utilizing AL6XN tubing. During heater production, over 30,000 tube ends were expanded, however, two tubes were identified to have failures as part of the tube expansion process. This paper shall describe the procedures utilized in developing and analyzing the tubesheet mock-up as well the actions taken to identify the root causes of the tube failures.

Recrystallization and Grain Growth of 316L Stainless Steel Wires

2014 ◽  
Vol 45 (8) ◽  
pp. 3446-3453 ◽  
Author(s):  
Xiuyun Zhao ◽  
Yong Liu ◽  
Yan Wang ◽  
Ping Feng ◽  
Huiping Tang
Keyword(s):  
Stainless Steel ◽  
Grain Growth ◽  
316L Stainless Steel ◽  
Steel Wires
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