What GR1 Titanium Coil Is
GR1 titanium coil is produced from Grade 1 commercially pure titanium, the softest, most formable and most corrosion resistant grade of the commercially pure titanium family. The coil is manufactured from titanium strip that is cold rolled and annealed, then wound into a coil for continuous feeding into forming, slitting, stamping or welding lines. Its defining combination is low density, high ductility and a passive oxide film that rebuilds itself instantly when damaged, which is why the material performs in chloride and oxidising environments where stainless steel fails.
Grade 1 is chosen rather than a higher strength grade whenever formability and corrosion resistance matter more than load carrying capacity. Deep drawn parts, expanded mesh, welded tube and thin wall heat exchanger components are typical of the grade.
Standards and Grade Equivalents
Coil and strip are supplied against recognised titanium standards, and the purchase order should always quote the standard together with the grade, the condition and the dimensions.
ASTM B265 - titanium and titanium alloy strip, sheet and plate; Grade 1 is the lowest strength commercially pure grade in this specification.
UNS R50250 - the unified numbering system identifier for Grade 1 titanium.
GB/T 3621 - Chinese standard for titanium and titanium alloy sheet, plate and strip, in which the equivalent designation is TA1.
GB/T 3620.1 - designation system for titanium and titanium alloy grades, used to cross reference TA1 with Grade 1.
Because the chemistry and mechanical values of Grade 1 and TA1 are aligned, a coil purchased to either designation can normally be certified against the other for reference, but the ordered specification and the inspection certificate supplied with the coil are what govern acceptance.
Chemical Composition
Grade 1 is unalloyed titanium with tightly controlled interstitial elements. Oxygen is the element that sets strength and ductility, so the oxygen limit is the reason Grade 1 is softer and more formable than Grade 2.
| Element | Requirement, % | Element | Requirement, % |
|---|---|---|---|
| Titanium | balance | Fe | max 0.20 |
| O | max 0.18 | C | max 0.08 |
| N | max 0.03 | H | max 0.015 |
Hydrogen is restricted to 0.015 percent because absorbed hydrogen can form brittle hydrides; the limit matters particularly for material that will be pickled, welded or used in cathodically protected equipment.
Mechanical and Physical Properties
| Property | Typical value, annealed coil |
|---|---|
| Tensile strength Rm | 240 MPa minimum |
| 0.2 % offset yield strength | 138 MPa minimum |
| Elongation | 24 % minimum |
| Density | 4.51 g/cm3 |
| Melting point | approximately 1668 C |
| Modulus of elasticity | approximately 100 GPa |
The low strength combined with very high elongation is what allows Grade 1 coil to be bent to tight radii, expanded into mesh and formed into complex heat exchanger plates without intermediate annealing. Where higher strength is required and formability can be reduced, Grade 2 with its higher oxygen content is the conventional next step.
Corrosion Performance and Temperature Limits
The passive titanium dioxide film gives the grade outstanding resistance to seawater, chloride solutions, oxidising acids and wet chlorine. In seawater service the material is effectively inert, with no measurable general corrosion rate under normal flow conditions, which is why Grade 1 coil is used for marine heat exchangers, desalination plant and offshore cooling systems.
The important limitations are equally well defined. Titanium is attacked by hydrofluoric acid and by concentrated reducing acids, and it can suffer crevice corrosion in hot, concentrated chloride brines when tight gaps allow the local chemistry to shift, typically above about 70 C in aggressive conditions. Design should therefore avoid unnecessary crevices and stagnant gaps in high temperature brine service. Fluoride-bearing water and dry chlorine gas also need specific review before titanium is specified.
On temperature, Grade 1 coil withstands service temperatures of about 400 C without significant distortion or loss of performance in typical applications, and most continuous duty designs keep well below that level to preserve strength margins. Above the useful range, oxidation and creep become the limiting factors rather than corrosion.
Applications
Shell and tube, plate and frame heat exchangers for seawater, brine and chemical cooling duty.
Chemical process equipment handling oxidising media, chlorides and hypochlorite.
Desalination and power plant cooling circuits, where the coil is formed into tube or plates.
Medical and surgical applications, where the high purity of the grade is important.
Electrodes, anodes and electrochemical components used in oxidising electrolytes.
Precision parts for marine hardware and instrumentation exposed to salt spray.
Coil Supply, Packaging and Ordering
Coil is supplied cold rolled and annealed, slit to the ordered width, with protective interleaving and a moisture barrier for sea transport. Packaging follows export seaworthy practice, using protective padding and secure containment to prevent edge damage and surface marking during handling. Shipment can be arranged by container, bulk or rail, loading from Tianjin, Qingdao or Shanghai, with delivery normally 15 to 35 days after order confirmation. Trade terms are quoted as FOB, CFR or CIF, and payment can be arranged by T/T or L/C at sight. Minimum order quantity is 5 metric tonnes, which suits both development quantities and production campaigns.
When ordering, state the standard and grade, the condition, the thickness and width, the coil inside diameter and the maximum coil weight, plus any requirement for edge condition or surface finish. Dimension and tolerance requirements should be referenced to the ordered standard so that permissible variations are unambiguous.
Handling and Storage Notes
Avoid contact with strong acids or strong alkaline solutions, which can deteriorate the coil surface.
Handle coils with care to prevent scratches or other mechanical damage; a scored surface is a site for localised attack.
Keep titanium separate from carbon steel during storage and fabrication, and use dedicated tools and brushes, so that iron contamination cannot be embedded in the surface.
Store dry and covered, with coils on a proper saddle or pallet so the wrap is not crushed.
Follow proper installation procedures when the coil is formed and assembled, including correct filler metal selection and clean joint preparation for welding.
Frequently Asked Questions
Q: Can GR1 titanium coil be used in a seawater environment?
Yes. Grade 1 titanium resists seawater corrosion effectively and is a standard material for marine heat exchangers and desalination equipment; the design should simply avoid tight crevices in hot, concentrated brine.
Q: What is the maximum temperature GR1 titanium coil can withstand?
The grade typically withstands temperatures up to about 400 C without significant distortion or loss of performance, although most continuous duty designs operate below that level to keep a working strength margin.
Q: Can GR1 titanium coil be welded?
Yes. Grade 1 welds readily using established titanium welding techniques, with inert gas shielding to protect the hot metal and the cooling weld from oxygen and nitrogen contamination.
Q: What is the difference between GR1 and GR2 titanium?
Both are commercially pure titanium. Grade 1 has the lower oxygen content, so it is softer, more formable and slightly less strong, while Grade 2 offers higher minimum strength with somewhat lower ductility.
Q: Does GR1 titanium coil need special cleaning or maintenance?
Periodic inspection for mechanical damage or surface contamination is enough in most services. Clean with a mild detergent or a titanium compatible cleaner, avoid steel wool and chloride-bearing cleaning agents, and never use hydrofluoric acid based products.
Q: Is GR1 titanium coil suitable for medical applications?
Yes. The high purity and excellent biocompatibility of the grade make it suitable for implants, surgical instruments and other medical components, where the material is normally ordered against the applicable medical titanium specification.
