Good Hot Working Property Chromium Nickel Stainless Steel TP304 / TP304L

TP304, TP304L, SUS304, SUS304L capillary for medical tube, electronic microtube etc

1 PRODUCT

TP304, TP304L, SUS304, SUS304L welded or seamless capillary.

2 EQUIVALENT DESIGNATION

UNS S30400, X5CrNi18-9, X5CrNi18-10, W.Nr. 1.4301, 0Cr18Ni9

UNS S30403, X2CrNi18-9, X2CrNi19-11, W.Nr. 1.4306, 1.4307, 00Cr19Ni10

3 APPLICATION

(1)Medical tubes such as syringes for injections, puncture syringes.

(2)All kinds of industrial tubes, small precision stainless steel tubes, dispensing syringes.

(3)Temperature guide tube, electronic thermometer, thermocouple protection tube, barbecue temperature probe tube, instrument protection tube, sensor tube, barbecue rub tube, thermostat tube, instrument tube, thermometer stainless steel tube, microbiological engineering tube.

(4) Core protector, pen holder

(5) Various electronic microtubes, optical fiber accessories, optical mixer

(6) Horological industry, T-bars with studs or screws, watch belt fittings, gem punches needle

(7) All kinds of antenna tubes, automobile tail antenna tubes, pull rod antenna tubes, stretch rod, mobile phone stretch antenna tubes, miniature antenna tubes, all kinds of stainless steel antenna.

(8) Stainless steel tubes for laser engraving equipment

(9) Fishing tackle pipe, fishing rod pipe

(10) All kinds of food and beverage industry pipe, feeding pipe

(11) Various stylus tubes, cell phone stylus, computer stylus tubes

4 OVERVIEW

304 stainless steel is the most widely used chromium - nickel stainless steel, with good corrosion resistance and heat resistance, low temperature strength and mechanical properties, good hot working property such as stamping and bending, no heat treatment hardening (operating temperature: -196 ~800), no magnetism. It has corrosion resistance in the atmosphere. If it is industrial atmosphere or heavily polluted area, it should be cleaned in time to avoid corrosion. Good machinability and weldability. It is suitable for food processing, storage and transportation, plate heat exchanger, corrugated tube, household articles, auto spare parts, medical instruments, building materials, chemistry, agriculture, ship parts, etc.

SUS304L has all the features of SUS304. It has excellent corrosion resistance, heat resistance, good corrosion resistance after welding or stress relief, and good deep drawing and polishing properties.

5 CHEMICAL COMPOSITION (wt%):

Table 1

5 PHYSICAL CONSTANTS

Density: 7.93 g/cm³

Melting point:1398-1420℃

Specific heat capacity (0~100°C,KJ·kgK): 0.50

Thermal conductivity: (W·m·K):(100℃)16.3,(500℃)21.5

Coefficient of linear expansion: (10·K):(0~100℃)17.2,(0~500℃)18.4

Electrical resistivity(20℃, 10Ω·m/m): 0.73

Longitudinal modulus of elasticity (20,KN/mm): 193

6 MECHANICAL PROPERTY

The material shall conform to the requirements as to tensile properties specified in Table 2.

These mechanical properties apply to tubing 1/8 in. (3.2 mm) and larger in outside diameter by 0.015 in. (0.38 mm) in wall thickness and heavier.

Smaller sizes are available meeting the minimum tensile strength specified in Table 2; however, yield strength is not generally determined on such sizes, and the minimum elongation shall be 25 %.

Table 2

A Grades TP 304L shall have a minimum tensile strength of 70 ksi (485 MPa) and a minimum yield strength of 25 ksi (170 MPa).

B Yield strength is not generally determined on tubing sizes smaller than 1/8 in. (3.2mm) in outside diameter or thinner than 0.015 in. (0.38 mm) wall, so yield strength is not required on such sizes. Also, the minimum elongation required on these smaller or thinner sizes is 25 %.

7 HEAT TREATMENT

Solid solution

The purpose is to make the carbides fully dissolved and retained in the austenite at room temperature, so as to obtain single phase austenite microstructure at room temperature, so that the steel has the highest corrosion resistance.

The heating temperature of solid solution treatment is generally higher, between 1050-1100°C, and is adjusted appropriately according to the carbon content. As the thermal conductivity of TP304 is very poor, not only through preheating and then quenching heating, but also in the solid solution treatment (quenching heating) of the heat preservation time is long. Special care must be taken to prevent carburization during solid solution treatment as carburization will increase the intercrystalline corrosion tendency of TP304 steel. Cooling medium, generally use water. The microstructure after solid solution treatment is generally single-phase austenite, but for stainless steel containing Ti, Niobium and Molybdenum, especially for castings, it also contains a small amount of ferrite. The hardness after solid solution treatment is generally around 135HBS.

Stress relieving annealing

In order to eliminate the residual stress after cold processing, stress relieving annealing is carried out at a lower temperature. Generally heated to 250-425°C, 300-350°C is often used. For steel without Titanium or Niobium, it should not exceed 450°C to avoid precipitation of chromium carbide and cause intergranular corrosion.

In order to eliminate the residual stress after welding and the sensitivity of steel to stress corrosion, the treatment is generally carried out at a higher temperature. Heating temperature is generally not less than 850°C. For steel containing Titanium or Niobium can be directly cooled in the air. For steel that does not contain Titanium or Niobium should be cooled with water to 500°C before being cooled in air.

Stabilization treatment

In order to prevent the austenitic stainless steels containing Titanium and Niobium from reducing their intergranular corrosion resistance due to the reduction of TiC and NbC during welding or solid solution treatment, the stainless steels need to be heated to a certain temperature (the temperature makes the carbide of chromium completely dissolve in the austenite, while TiC and NbC only partially dissolve) before slow cooling. In the cooling process, the carbon in the steel is fully combined with Titanium and Niobium, and stable TiC and NbC are precipitated out, while chromium carbide is not precipitated out, thus eliminating the intercrystalline corrosion tendency of TP304 steel.

8 PROCESS

Tube blank → Peeling → Blanking → Heating → Hot piercing → Cooling → Finishing → Pickling → Lubricating

→ Cold rolling → Degrease → Heat treatment → Straightening → Tube cutting → Pickling → Inspection → Packing.

OR

Tube blank → Peeling → Blanking → Inner hole drilling → Lubricating → Cold rolling or drawing → Degrease

→ Bright annealing → Straightening → ID and OD surface polishing → Inspection → Packing.

9 DIMENSION

Permissible variations in dimensions

10 FLARING TEST

A section of tube approximately 4 in.(101.6 mm) in length shall stand being flared with a tool having a 60°included angle until the tube at the mouth of the flare has been expanded to the following percentages without cracking or showing flaws:

11 Hydrostatic, Air Underwater Pressure Test, or Nondestructive Electric Test

Each tube shall be subjected to the hydrostatic test, air underwater pressure test, or nondestructive electric test. The

type of test to be used shall be at the option of the manufacturer, unless otherwise specified in the purchase order.

Hydrostatic Test

Each tube shall be subjected to a hydrostatic test at a test pressure not exceeding 1000 psi (6.89MPa).

Air Underwater Pressure Test

Each tube shall be subjected to an air underwater pressure test, at a test pressure as given by the following equation or 500 psi (3.4 MPa), whichever is less: P=2St/D

where:

P = air pressure, psi or MPa

S = allowable fiber stress of 16,000 psi (110.3 MPa),

t = specified wall thickness, in. or mm, and

D = specified outside diameter, in. or mm.

Nondestructive Electric Test

Each tube shall be subjected to a nondestructive electric test that is capable of detecting imperfections with a

depth exceeding 10 % of the wall thickness or 0.002 in. (0.05mm), whichever is greater. Testing will not be required on sizes under 0.125 in. (3.18 mm) in outside diameter. However, at the option of the purchaser, tubing to be drawn to a diameter under 0.125 in. may be tested while in the range from 0.156 in. (3.97mm) to 0.125 in. outside diameter, and any defects that are found shall be culled out before any further reductions are made.

12 PRODUCT CAPACITY

OD:0.25-8.0 mm

WT:0.065-3.0 mm

Concentricity: good

Straightness:≤1mm/m

Surface:2B, BA, Mirror, sandblasted surface, passive surface.

Annealing surface,fine drawing bright surface Ra≤0.8μm,finely polished ID and OD Ra≤0.2-0.4μm. (possible Ra 0.1μm at request).

13 STANDARD SPECIFICATION

GB/T 3090 Stainless steel small diameter seamless steel tube

GBT 18457 Stainless steel needle for manufacturing medical machinery

GB 4234 Stainless steel for surgical implants

YBT 4513-2017 Welded stainless steel tubes for medical gases and vacuums

ASTM A632 Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service

ISO 5832-1-2016 Implants for surgery metallic materials - Part 1 Wrought stainless steel

ISO 9626-2016 Stainless steel needle tubing for the manufacture of medical devices requirements and test methods

14 COMPETITIVE ADVANTAGE

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Patented technologies.

(4) High performance.

15 BUSINESS TERM